Freezing 3yr old son's bedroom HELP!

[PhoenixServices]

My two penny worth, some of these designer rads have baffles and should be piped up a certain way round. I.e flow to inlet. Had this before they don't perform as well. If rebalancing and changing trvs fail, flip the rad round and see how it performs.

 

[doitmyself]

I know the limitations of an IR THERMOMETER and have also recorded inlet and outlet temps at each radiator in the system (have excel sheet with data representing hours work). I use black tape on the copper pipe to get more reliable reading. Top of rad (white surface) is reasonable indication with IR thermometer.

You seem to be doing everything 'by the book'. Could you post the most recent results?

I see no change in the system temps at speed 2.

Interesting. Increasing the speed should produce a reduction in the differential, and vice-versa.

checked the thermostat pins, problem rads have pins which stick out the same amount at the pins on TRVs on rads that work fine, and are free to move up/down, so again doubt that is the issue. The lockshields are also fully open.

On some TRVs the pins are not connected to the plunger which blocks the flow, so free movement of the pin is not significant. Try giving the side of the TRV body some sharp taps with a hammer.

You say the LS valves are fully open, is this because you have balanced the system using the built-in balancer of the Danfoss TRVs?

 

[Geyser]

My two penny worth, some of these designer rads have baffles and should be piped up a certain way round. I.e flow to inlet. Had this before they don't perform as well. If rebalancing and changing trvs fail, flip the rad round and see how it performs.

Had this as well. Do we know what these designer rads are?

 

[PriestyUK]

Phoenix Services may have a point, I have also found on one job in a small-ish office block that 2 end rads didnt get very hot (one of which was the MD's office) We changed TRV's and radiators, we pulled it through on the drain cocks to make sure no air or $hit in the pipework and still the same problem. All the other rads got hot, it was only by chance that we thought lets just change the pump that it cured the problem. Pumped seemed to be running fine but some how it just wasn't man enough anymore to reach them last 2 rads whether the impeller blades had worn down I don't know but changed that pumped and MD was finally happy.

 

[Leo21]

You seem to be doing everything 'by the book'. Could you post the most recent results?



Interesting. Increasing the speed should produce a reduction in the differential, and vice-versa.


On some TRVs the pins are not connected to the plunger which blocks the flow, so free movement of the pin is not significant. Try giving the side of the TRV body some sharp taps with a hammer.

You say the LS valves are fully open, is this because you have balanced the system using the built-in balancer of the Danfoss TRVs?

You dont tap trv,s from the side. Specially not sharply, you tap them on the pin! Get your facts right before giving advise. Perhaps contact the mods with your qualifications, so we know your actually qualified to advise these poor unsuspecting people.

 

[Leo21]

Hi

Moved into a property last year, combi system installed 3-5 years ago. Ready to start ripping radiators out as heating system is doing my head in with hours spent trying to resolve an issue with poor rate of heating on 2 radiators and a 3yr old encased in ice most mornings as a result! Apologies for the length of this post.

Got a 16 radiator combi system in bungalo (2 levels, 10 rads downstairs and 6 upstairs). Vokera Compact Combi 35HE model (35kw). Every rad has TRV and Lockshield (Danfoss RAS-C2). System heats fine, delivering flow temp of 75 and return 55 at the boiler when system up to full temp within 30-60min. House is 2 pipe flow and return system with rads brancing off it, but there appears to be two (or more) loops - once downstairs and possibly 2 upstairs (feeding bedrooms to front and rear of property respectively). Got a HIVE thermostat controlling the overall system located in an area in the middle of the home with adjacent ratiator TRVs set to 5).Finally, rads are all rated around 1.25KW at 80 degrees and are the designer range (look like old school rads with open tubes if that makes sense)

Problem arises on 2 radiators (front lounge and bedroom above it, which is 3 yr old's room). Both are at the farthest point from the boiler at the end of the lines (which I think is the issue here) and both refuse to heat beyond 55-degrees (measured at top middle of radiator using an infrared thermometer) after heating on for a couple of hours. If I leave heating on for a long time, like 4 hrs, the bedroom radiator will slowly warm up to ~60degrees.

Problem is in mornings when heating comes on at 6:30 am, kids get up at 7:30 and 3yr olds room is still like an icebox with radiator barely warm (same applies to front room downstairs) - perhaps reaching only 45degrees after an hour. This is despite the inlet pipe to both radiators being hot to touch (around 65-degrees after 30-min I would estimate). All the other radiators in the house come up to 60-65degrees temp quickly, but these two are just hopeless and result in 2 really cold rooms in the mornings. I know I could start the heating at 4am to ensure 3yr old room is toasty come 7:30 but that's just daft.

What I have done so far:

#1 added fernox to be on safe side, but water is clear and no sign of gunk when I bled all radiators (very little air in system - also checked all lockshileds and TRVs worked fine by removing trv and moving pin up and down in the case of the latter);

#2 removed all TRVs and opened lockshields 100%, turned room thermostat to 30-degree and blasted heating for 2hours - max temp in problem rooms 50-degrees;

#3 started balancing the system by closing down the lockshields progressively until 1st rad in the system was 25% open, leaving both problem radiators FULLY OPEN at locakshields re-ran test: max tem 55-degrees in problem rooms after 2 hours;

#4 closed down lockshields on radiators downstairs even further (apart from lounge) which has has little effect on lounge or 3yr old bedroom;

#5 Closed all radiators apart from lounge and 3yr olds room and ran heating - again despite hot inlet pipes to rads, they only heated to 55-degrees after two hours;

Observations.

#6 CHecked pump is working - 3 stage pump and set to each speed noting change in speed (audible) therefore assuming working OK,

#7 3yr old's brothers room which is the 2nd last in the line, is roassting with radiator hitting 65 degree temp in 30-60-min and after 2 hours there is still a clear 10-degree difference between them. Turnng off this radiator, which is like 8 ft away throught the partition wall from his brother does not improve the heating rate of the 3yr olds radiator one jot;

#8 problem radiators have good temp profile - hot at top and probably 5-10 degree difference at bottom, so I dont think they are sludged up and bled water is cystal clear.

Current thinking on possibilities:

#8 Pump is actually failing and not got enough power to push heat to 2 radiators at the end of the line;
#9 Got a blockage/restriction in the two problem rads (could be sludge, dodgy TRV pin, lockshield or airlock);

Regarding 9, what are the chances of both radiators having the same blockage issue. Too much of a co-incidence that they are each at the end of their respective lines in my view so I question whether a blockage is the issue - that said, the inlet pipes are roasting with the outlet pipes warm (Im seeing 20degree temp drop over the inlet and outlet pipes on these rads);

Airlock - could I have an airlock in both rads? Surely this would prevent ANY heating of the rads Vs what I am seeing,i.e., just not heating enough.

Any thoughts, suggestions for further tests I could do or solutions would be gratefully received. spent hours on this and still have a cold 3yr old bedroom in the morning and a inhabitable lounge! Current snowy conditions makes solving this a priority.

Ufortunately there's a flaw in our system on here, please only take advise from members with gs registered, plumbers arms or trusted badges.

 

[stevetheplumber]

actually leo i find a sharp tap on the side works the best tapping the pin is pushing the valve shut i use the handle of a spanner

 

[Leo21]

Thanks for that Steve, give him ammo.

 

[smglasgow]

Just a quick thanks to all who have contributed, much appreciated.

Answers to least couple of points:

- no markings on rads to show what model, but I suspect they are STELRAD CLASSIC, 3 COLUMN DESIGN based on what I see online - how do you know if they are directional as one poster commented?;

- I dont want to inflict data from an excel sheet on everyone, so inclined not to try and post that lot doityouself!

- sharp tap to side of TRVs interesting idea - Ill stand by with a bucket just in case......and as per latest post, inclined to use handle of hammer then if brave ramp up to using the head!

DOITYOURSELF COmment "You say the LS valves are fully open, is this because you have balanced the system using the built-in balancer of the Danfoss TRVs?"

- Not sure what you mean by built-in balancer. but l said LS valves are fully open as I took the cap off and unwound them using 6mm alan key to their furthest open position.

- Pump replacement is where I am heading if the hammer tap doesnt work, but as this would involve a drain down of the system I could also remove the problem rads and thoroughly flush, test lockshield and trv flow BEFORE installing new pump but basically have all the bits to hand should I need them: (Pump, 2 x TRVs + 2 x lOCKSHIELDS) then only install the pump and valves if I find the current ones work and it was indeed the rads that somehow were gunked up (yet they only have a 5 degree temp diff from top to bottom so doubt that) -Q then becomes what pump should I replace the existing Vokera 35HE pump with - same or beefed up?

Final thought is I have airlocks, and no one has yet confirmed if an airlocked radiator can get hot,just not REALLY hot or if it would always be stone cold.

 

[joni os]

actually leo i find a sharp tap on the side works the best tapping the pin is pushing the valve shut i use the handle of a spanner

Hold block of wood on opposite side to focus effect of tap.

 

[doitmyself]

You dont tap trv,s from the side. Specially not sharply, you tap them on the pin! Get your facts right before giving advise.

Sorry to disagree with you, but I have seen advice on several forums, from obviously experienced contributors, advising people to tap the side of the TRV body to loosen the plunger. Tapping on the pin will only encourage the plunger to stick further into the seat and may damage the pin.

 

[Dotty]

Sorry to disagree with you, but I have seen advice on several forums, from obviously experienced contributors, advising people to tap the side of the TRV body to loosen the plunger. Tapping on the pin will only encourage the plunger to stick further into the seat and may damage the pin.

So what you're saying is that really you haven't got a clue but because someone else on another forum said it's so makes it true.

Take a good hard look at Leo's Trusted Advisor badge. Remember your name and consider your own inexperience.

 

[Leo21]

Sorry to disagree with you, but I have seen advice on several forums, from obviously experienced contributors, advising people to tap the side of the TRV body to loosen the plunger. Tapping on the pin will only encourage the plunger to stick further into the seat and may damage the pin.

Now you see the difference here is, I'm qualified with over twenty years experience. I'm not parroting someone else's posts pretending I know what I'm talking about.
I've been doing them from the top since the 80,s with minimum failures. I find the side method takes more force.
And I'll ask again, any qualifications or experience to back your aparantly knowledgable posts up?

 

[doitmyself]

Not sure what you mean by built-in balancer. but l said LS valves are fully open as I took the cap off and unwound them using 6mm alan key to their furthest open position.

The RAS-C2 head can be used with two different bodies. The RA-N body has a ring numbered 1 to N and the flo through the valve can be adjusted by setting to the appropriate number. By default the valve is set to N. If your LS valve is adjusted using an allen key then it is probably a Danfoss valve. The Danfoss recommended adjustment range is ¼ to 4 turns open. If you want to have another go at balancing, start with all LS valves ½ turn open.

 

[Dotty]

You are barking up the wrong tree. And I notice that the majority of that is copied directly from the Danfoss MI's.

What experience do you actually have?

Because I will not have inaccurate advice given on this forum .

 

[doitmyself]

I'm qualified with over twenty years experience.

I see you are GS registered and a PA member - that's all I know about you.

I've been doing them from the top since the 80,s with minimum failures. I find the side method takes more force.

May be it does take more force, but it's less likely to damage the innards of the valve.

As for qualifications, - my Forum name should tell you. Experience - looking after my own heating systems for nearly 40 years: balancing; installing motorized valves; programmers and thermostats; converting a gravity/pumped to C plan; relocating an F/E tank for a friend because it was too near the boiler, which had been relocated from ground floor to first floor, so the static head was too small and the system was pumping over. (The installers "solution" was to turn the pump down, which immediately produced other problems); etc etc. If any work to the boiler has been required I immediately call in a trusted GSR engineer.

 

[SimonG]

OP will you please give the trv's a sharp tap and a wiggle of the pin. Then let us know the score. Cheers.

 

[SimonG]

I see you are GS registered and a PA member - that's all I know about you.


May be it does take more force, but it's less likely to damage the innards of the valve.

As for qualifications, - my Forum name should tell you. Experience - looking after my own heating systems for nearly 40 years: balancing; installing motorized valves; programmers and thermostats; converting a gravity/pumped to C plan; relocating an F/E tank for a friend because it was too near the boiler, which had been relocated from ground floor to first floor, so the static head was too small and the system was pumping over. (The installers "solution" was to turn the pump down, which immediately produced other problems); etc etc. If any work to the boiler has been required I immediately call in a trusted GSR engineer.

Why didnt you leave the tank and convert to low head situation?

 

[doitmyself]

You are barking up the wrong tree. And I notice that the majority of that is copied directly from the Danfoss MI's.

How am I barking up the wrong tree?

I was not copying anything from Danfoss MI; I was already aware of the fact that Danfoss made a pre-settable body compatible with the C2 head.

What experience do you actually have?

Already answered.

Because I will not have inaccurate advice given on this forum .

I agree wholeheartedly; please advise me which advice in this topic is inaccurate.

 

[SimonG]

How am I barking up the wrong tree?

I was not copying anything from Danfoss MI; I was already aware of the fact that Danfoss made a pre-settable body compatible with the C2 head.


Already answered.


I agree wholeheartedly; please advise me which advice in this topic is inaccurate.

Its not a balancing issue.

 

[jonnyswamp]

I see you are GS registered and a PA member - that's all I know about you.


May be it does take more force, but it's less likely to damage the innards of the valve.

As for qualifications, - my Forum name should tell you. Experience - looking after my own heating systems for nearly 40 years: balancing; installing motorized valves; programmers and thermostats; converting a gravity/pumped to C plan; relocating an F/E tank for a friend because it was too near the boiler, which had been relocated from ground floor to first floor, so the static head was too small and the system was pumping over. (The installers "solution" was to turn the pump down, which immediately produced other problems); etc etc. If any work to the boiler has been required I immediately call in a trusted GSR engineer.

Not going to jump all over you fella but, the majority of home owners/diyers that come on here for advice want advice based on actual experience, not a paragraph lifted straight from mi's ins or a text book
The reality between theoretical experience and practical are sometimes far apart and can require
real world exp to rectify/overcome the problems they may have

 

[doitmyself]

Why didn't you leave the tank and convert to low head situation?

Because the tank needed replacing in any case, so while I was about it I decided to relocate. In any case the boiler's MIs specify a static head of 1m above top of the boiler, without showing a "low head" option, I followed the MIs, as frequently advised on many Forums.

 

[Dotty]

How am I barking up the wrong tree?

I was not copying anything from Danfoss MI; I was already aware of the fact that Danfoss made a pre-settable body compatible with the C2 head.


Already answered.


I agree wholeheartedly; please advise me which advice in this topic is inaccurate.

Its not a balancing issue.

As Simon said. It is NOT a balancing issue. And dabbling with your own and a friends heating systems does not make you experienced. It makes you familiar with those systems.

You, at the moment, are barking up the wrong tree by carrying on about the balancing. Your methodology of that, I will add, is also flawed. You have not read the op in the slightest.

So, do you want to want to try again?

 

[Leo21]

I see you are GS registered and a PA member - that's all I know about you.


May be it does take more force, but it's less likely to damage the innards of the valve.


I once pulled my wobbly tooth out with a price of string. Does that make me a dentist?
You've got no grounds advising people in here through your experience. Yours and a friends house isn't enough.

As for qualifications, - my Forum name should tell you. Experience - looking after my own heating systems for nearly 40 years: balancing; installing motorized valves; programmers and thermostats; converting a gravity/pumped to C plan; relocating an F/E tank for a friend because it was too near the boiler, which had been relocated from ground floor to first floor, so the static head was too small and the system was pumping over. (The installers "solution" was to turn the pump down, which immediately produced other problems); etc etc. If any work to the boiler has been required I immediately call in a trusted GSR engineer.

Well done you! You fixed an issue at some stage.

 

[rpm]

Hi guys, since joining ukpf 3yrs ago this month I`ve read every post, looked at every photograph and learned loads so can I call myself a plumber with experience and argue with real plumbers in the real world ?

Please, pretty please ! lol