Does this sound like the pump?? Pulling my hair out!!

[chezabha]

Hi. Been having problems with CH since last year. I will try to cover as much info as I can in the hope one of you experienced guys might advise on the issue.
I have 11 rads all but one fitted with TRV's.
Ideal classic slimline ff250 (fitted in the garage)
Cold water tank with CH header tank in the loft
Two storey house
Pipes are 15mm microbore

The rads downstairs are not heating up as they should. I've checked all trv's and replaced them. The largest rad in the house which is 1100x600 appears to have the "sludge" arc at the bottom of the unit. I've run Fernox sludge
Remover through the system over the last week. I shut off the rads upstairs periodically so the chemical was concentrated on the cold downstairs rads.
Drained the system yesterday and refilled with no change. Drained again and back filled. Upstairs rads are boiling. Downstairs are cold. I then opened the lock shield and connected a hose to outside and drained some water. Each of the downstairs rads warmed up to the point where they were boiling. By the time I finished this procedure the rads were going cold again.

I'm thinking that the pump is not operating correctly and is unablebto push the water up and down every stud wall in the downstairs of the property. I've tried to adjust the speed of the pump to full but it's no better.

Does anyone have any ideas on what I can try?

Thanks in advance

 

[BLOD]

You could try removing the downstairs rads and flushing them through with a garden hose (mains pressure).
See if this gets rid of the Sludge mound.

Check the resistance of the pump - should give an idea if it's wearing out.

 

[BLOD]

Also if you've got a bypass, check it's not fully open.

 

[andyplumber]

it does sound like your pump is wearing out, also check your locksheild valves upstairs are they fully open your heating may need balancing.

 

[chezabha]

I connected the outdoor hose to the downstairs rad in the living room and another to the one near the front door and left the water flowing for 20 minutes. How do I check the pump resistance?

 

[BLOD]

turn electricity off and disconnect wires at pump.
Check the ohms between live & neutral terms on pump, you should get approx 150 to 250 ohms.

 

[chezabha]

Ok. Will give that a bash and ket you know

Thanks for the help so far

 

[tamz]

I agree with Blod. Check your pump resistance and take the rads outside and run mains water through them with a hose which will clear more muck than a powerflush.

 

[dontknowitall]

Classic sympton of a failed pump (or pump not working) is hot rads upstairs and cold downstairs.

 

[armourer]

Turn all of the hot radiators upstairs off and fully open the downstairs see what happens to the downstairs ones?

How many drops have you got to the downstairs rads? could be if its if a single drop and you have a sludge build up the resistance will cause it to ignore the downstairs.

Does sound like a pump struggling though just trying to eliminate balancing and sludge.

 

[SafeGasInstall]

get the local heating engineer to have a look before snow comes

 

[chezabha]

get the local heating engineer to have a look before snow comes

The local heating engineer came out last week as I didn't know what else to do. They told me to add the Fernox and see how it goes. They said for them to check, bleed and recheck the system would be time consuming and cost me alot of cash. Hence my progress to date

 

[chezabha]

Turn all of the hot radiators upstairs off and fully open the downstairs see what happens to the downstairs ones?

How many drops have you got to the downstairs rads? could be if its if a single drop and you have a sludge build up the resistance will cause it to ignore the downstairs.

Does sound like a pump struggling though just trying to eliminate balancing and sludge.

When all rads upstairs are turned off there is a minimal rise in heat but not really anything to shout about! There are 5 rads downstairs and each one has a drop from the upper level. I've checked this with a pipe sensor on each
wall
If I go ahead and buy a new pump should I go for a more powerful one than the one I have just now a Grundfos 15-50 I think

 

[armourer]

just replace it with a !5-60 then, straight swop.
Or even just change the head.

 

[tamz]

If a 15-50 is what is already fitted and the heating has worked fine before, then there is no need to fit a 15 -60.
Most of the problems on open systems occur because someone has changed a pump and set it wrong which leads to the system drawing air which means corrosion and sludge.

When you change the pump it should be set to the lowest setting it will work at.

 

[Gas Jim]

Sounds to me that the pump has seized after CH being off over the summer.

 

[chezabha]

Ok. All the advice has been taken on board and understood. I'll get me a new pump this week and give it a whirl. I'll post back next weekend with the results as I'm away on business this week.

Thanks again for everyone's help and advice.

 

[jam1979]

hi u cld have an airlock in ur system turn upstairs rad off till down stairs rads heat up then open all upstairs rads then bleed all rads in the house hope this helps

 

[arran197]

Pump doesn't cost a lot to change and won't take too long if you just swap the heads.

 

[chezabha]

Hi all. I finally replaced the pump last week. I must say the heating is far more responsive than it was before so thanks for the advice. The only issue I still have is the living room rad will heat up, but the lock shield on the return side of the rad remains cold as does the very corner of the rad. I've had the rad off and blasted it with water which appeared to be flowing through ok. I've also opened the leak off valve whilst disconnected from the rad and there appears not to be a blockage. I'm assuming that I have a faulty rad and need it replacing? The rad will stay hot for a while then cool down as there is no circulation
I thought I would ask the experts before I spend more on the heating system!

 

[mrlennie]

just a stab in the dark but does it not sound the lock shield is faulty?

 

[arran197]

Ye, could be the lock shield. You could try removing the rad, getting a bucket and opening the valve, making sure the water shoots out of it.

 

[mrlennie]

Ye, could be the lock shield. You could try removing the rad, getting a bucket and opening the valve, making sure the water shoots out of it.

Agreed, its a very simple job.

 

[chezabha]

Hi. I've done this in the past and water is freely coming through. I now have all other rads in the house turned off and the lock shield has finally warmed up but only warmed up. The valve on the other side is so hot you can hardly touch it. I might try to replace it before forking out on a new rad.

 

[mrlennie]

If you have tested rad and tested lockshield then sounds like a block after the lockshield. water may freely come out because the pipe is full of water. How much water did you remove when you opened the valve?