Radiator not working

[Diyer171]

Hi All,
I recently installed a radiator and it only seems to be Luke warm along the base whilst the rest is stone cold. I have repressurised the system and bled the radiator the thermostat is set to the max setting and the other valve is turned all the way anti clockwise ( I have also tried it all the way clockwise). All other radiators are hot even the one on the other side of the same wall. Any ideas are welcome. I have since installed another radiator that works just fine so I can’t seem to think what the issue could be.

 

[ShaunCorbs]

Are the pipes kinked at the bottom ? (10mm)

 

[SimonG]

Did it have a specific flow and return connection and its connected in reverse?

Have you disconnected valves and checked you have good flow through both valves?

Have you shut down all other rads on the system leaving that one open in case it's an airlock?

 

[Ben-gee]

It is either flow /return the wrong way around, of fitted upside down.

Who’d have thought these vertical rads would be so finickety?

The thing is they’re not marked quite often, in which case you need to look inside with torch / mirror ( or poke a wire in) to see where the baffle is located.

 

[Stu-B]

Agree with ben-gee, these are flow/return specific, get them wrong and the dont warm up

 

[Diyer171]

It is either flow /return the wrong way around, of fitted upside down.

Who’d have thought these vertical rads would be so finickety?

The thing is they’re not marked quite often, in which case you need to look inside with torch / mirror ( or poke a wire in) to see where the baffle is located.
[/QUOT

Hi All,
I recently installed a radiator and it only seems to be Luke warm along the base whilst the rest is stone cold. I have repressurised the system and bled the radiator the thermostat is set to the max setting and the other valve is turned all the way anti clockwise ( I have also tried it all the way clockwise). All other radiators are hot even the one on the other side of the same wall. Any ideas are welcome. I have since installed another radiator that works just fine so I can’t seem to think what the issue could be.View attachment 45538

thanks all for your help, I have just checked the valves and they are bi-directional so if I’m not mistaken then flow and return shouldn’t be a problem and the old radiator had the thermostat valve on the same side. I don’t think the copper is kinked as the rad filled up quite fast. So I think it must be upside down. Having looked at it now I noticed that it’s mirrored and thinking back the bleeding valve and the blanking plug came loose so I must have put them on myself. Is there anyway of checking before emptying the rad and turning it around? Surely there should be a “this way up” sign!
Being Australian I am pretty lost when it comes to radiators. Thanks in advance.

 

[Gasmk1]

If it’s mark it will just be a little indentation on the spreader

 

[Ben-gee]

The flow/return possible issue is not related to the valves, it’s the physical radiator itself.

The water comes in along the bottom rail and there is a baffle quite close to one end, this directs the water up through the rest of the rad before it exits at the other end of the bottom rail. If flow and return are the wrong way around then the water “short circuits”, it goes across most of the rad before it hits the baffle, this results in the rad heating up very slowly indeed.

If basically ONLY the bottom rail gets hot then you probably have it upside down, as there is usually no baffle in the top rail ( possibly your bottom rail!) so the water goes straight through. (You get a small amount of heat transference through the metal of the rad of course)
You should be able to feel the difference between ‘upside down‘ and flow/return wrong by feeling rad when you initially switch it on.

 

[John.g]

Do "tall" rads without a baffle heat up more slowly or what?,

 

[Diyer171]

So I have pulled the radiator off and I can see right through where the bleed valve and locking but is which makes me think it’s not upside down. The baffle is on the left and so is the thermostat valve so I’m really not sure what the problem is.

 

[John.g]

Have you checked that the flow is from left to right?. Also if only one vent on the top right maybe consider fitting another one on the opposite end. With the circ pump off, shut the lockshield valve and open the TRV fully, open the vent and note the water force then reverse the procedure and note the water force again and compare, maybe repeat with boiler/circ pump on. Maybe consider draining rad down completely, (fit second vent?) and fill very slowly from the left hand side with both vents fully open and see how you get on.

 

[Diyer171]

Have you checked that the flow is from left to right?. Also if only one vent on the top right maybe consider fitting another one on the opposite end. With the circ pump off, shut the lockshield valve and open the TRV fully, open the vent and note the water force then reverse the procedure and note the water force again and compare, maybe repeat with boiler/circ pump on. Maybe consider draining rad down completely, (fit second vent?) and fill very slowly from the left hand side with both vents fully open and see how you get on.

Hi John,
so I have checked that the Baffle is on the left hand side and the TRV is on the left beyond that I haven’t done any other checks. I have noticed that the copper on the right is quite warm and the one on the left (the TRV) is cold. Could this mean that I need to switch them? The old radiator was setup the same way as it is now so I would be surprised.

 

[Ben-gee]

So I have pulled the radiator off and I can see right through where the bleed valve and locking but is which makes me think it’s not upside down. The baffle is on the left and so is the thermostat valve so I’m really not sure what the problem is.

So sounds like flow/return are the wrong way around.
Easiest is to flip the rad around front to back.

 

[John.g]

Are you saying that if the baffle is on the left bottom that the flow is from left to right and if on the right bottom, flow is from right to left?
[automerge]1601738477[/automerge]

Hi John,
so I have checked that the Baffle is on the left hand side and the TRV is on the left beyond that I haven’t done any other checks. I have noticed that the copper on the right is quite warm and the one on the left (the TRV) is cold. Could this mean that I need to switch them? The old radiator was setup the same way as it is now so I would be surprised.

To be honest I don' really know as I would have thought that the baffle should be closest to the flow , I only base this on my own horizontal rads, if one is shut off until the boiler reaches normal working temperature and I then open up the valves, the hot water will rise straight up in the first say 6 ins and then start moving along the top and start heating the remainder of the rad from top down, this might indicate that the baffle should be closest to the flow end but yours isn't and I include a quote from someone below who has a vertical rad plumbed like yours, ie the baffle at the return end.
"I have now received a replacement sixteen column vertical radiator. On examination I have noted the following:


It is clearly marked with inlet and outlet labels, BBOE connection (the others were not so marked);
There is a baffle about a quarter in from the outlet side. There were no baffles in the other radiators. The presence of the baffle indicates that the flow has to pass up to three quarters along the bottom inlet before being forced up to the top and then back down again to the outlet. This is a much better arrangement and should give a more even heat distribution;
The colour is off-white. Not a problem as it matches the room colour;
The horizontal tubes are closer together giving about 10mm clearance on the bottom bracket fixings for the old radiator."

 

[SimonG]

Have we even confirmed good flow from both valves before all this kerfuffle with the rad itself?

 

[king of pipes]

Vertical rads are notorious for trapping air in them I have had issue after fitting these, as stated above is there a good flow through each valve ? Is it fitted in the correct way although bi directional the valves work better in my opinion if the flow is the Trv and the return is the lockshield ? I always install a Alladin auto air vent aswell as the manual air vent which helps to keep the rad free of air, it may also be there isn't enough head pressure to even fill this type of rad as each section of the rad air locks at the top , there is a way of doing this manually it's called back filling if you are competent to do it ? Isolate the cold feed cap off the vent , connect a hose from a the mains water supply ideally from a outside tap you maybe able to back fill though a drain point but sometimes this may not work so it may need a modification to allow this, always use a jubilee clip on the connection you don't want a the hose flying off while you're venting the rad , please only do this if your confident your able to ? Lock open the zone valve on the heating turn on the mains water slowly half a turn go to the rad isolate the trv and vent the vertical rad of air slowly and all the other rads, then it's a reverse process before a heat test it may also be beneficial to close off the rads closest to the boiler for a while get a good flow going through the rest . Best of luck Kop

 

[John.g]

Do you yourself fit those vertical rads with the baffle closest to the flow or is it manufacturer specific?

 

[Diyer171]

Have we even confirmed good flow from both valves before all this kerfuffle with the rad itself?

I can confirm that there is good flow from both radiators. Directly on the other side of the wall is another radiator which mirrors the valve setup so I’m thinking that the plumber

Have we even confirmed good flow from both valves before all this kerfuffle with the rad itself?

hi Simon,
yep good flow from both. I’m going to switch the valves over in case that helps.
[automerge]1601828502[/automerge]
Ok so once again I am baffled, I swapped the two valves around so the TRV is now on the right and now 2 other radiators don’t work downstairs. So I’m guessing it was right the first time.

 

[ShaunCorbs]

You don’t have a one pipe system do you as changing the trv to the other side shouldn’t effect the other rads

 

[Diyer171]

You don’t have a one pipe system do you as changing the trv to the other side shouldn’t effect the other rads

I guess I was a bit hasty to comment as they have finally come on now but all other rads must have been blazing for 30mins before those 3 had any heat. They are still not putting out as much heat as the others.

 

[king of pipes]

Do you yourself fit those vertical rads with the baffle closest to the flow or is it manufacturer specific?

As manufacturers states 👍

 

[John.g]

I guess I was a bit hasty to comment as they have finally come on now but all other rads must have been blazing for 30mins before those 3 had any heat. They are still not putting out as much heat as the others.

Don't know if you can still hang that column rad or not if you turn it around to get the baffle nearest the flow end to see if it improves, in the absence of any markings or manufacturer's instructions.

 

[Diyer171]

thanks for all the advice! I guess switching out the valves has improved the flow. I guess it’s just time to rebalance the system now. From what I have googled I guess I just turn all the hot rads down to a 1/4 turn on the lock shield and leave the cold ones on full?!

 

[king of pipes]

Alan Hart on you tube has a video on how to do it . Regards kop

 

[John.g]

thanks for all the advice! I guess switching out the valves has improved the flow. I guess it’s just time to rebalance the system now. From what I have googled I guess I just turn all the hot rads down to a 1/4 turn on the lock shield and leave the cold ones on full?!

Came across a bit of info that you may (or may not) be interested in, I changed out some of my TRVs recently and used EPH (15mm), I measured the flow rate through one of them both ways and got the same, 3.8 LPM @ 0.5M head, I didn't renew the lock shield valves which are supplied with the TRVs but got exactly the same flow rates on one of these, these flow rates are very close to the manufacturers flow rate of 1 M3/hour @ 1 bar head. Balancing will hopefully solve your problem.