Vitodens 200 - central heating - upstairs rads hot - downstairs not..

[allybaba1975]

Hi All,

I hope you can help. I have problem with the above boiler. It has always worked fine for the last 2-3 years but now have issue with radiators heating up, been a few months since had CH turned on. hot water heating up fine from the boiler. All upstairs rads seem fine, but downstairs only 2 out of 5 heating up - but not getting hot hot! the 2 rads seem hotter at the top than the bottom?! I have bled all the rads - have googled the problem and it indicates the pump could be at fault, hot water not able to reach downstairs rads? Could this apply to my boiler, i read that the circulation pump kicks in at least once per day even if the CH is not used? Would the boiler not register an error if the pump was not working correctly?? Any help you can offer would be greatly appreciated.

Kind Regards

Alan Craddock

 

[Clint 1979]

Sounds like sludge in the system, your best bet would be to get someone in to drain the system and see what colour the water is (black would indicate black oxide sludge, corrosion in the system), you may need to get your system flushed and possibly have a magnetic filter fitted whilst you're at it.
If your pump didnt work boiler wouldn't work (unless its noisy and slowing down), but if all the upstairs rads and 2 of 5 downstairs are getting hot i would say your circulating pump sounds ok!

Good luck

 

[Jay Jay]

Hi All,

I hope you can help. I have problem with the above boiler. It has always worked fine for the last 2-3 years but now have issue with radiators heating up, been a few months since had CH turned on. hot water heating up fine from the boiler. All upstairs rads seem fine, but downstairs only 2 out of 5 heating up - but not getting hot hot! the 2 rads seem hotter at the top than the bottom?! I have bled all the rads - have googled the problem and it indicates the pump could be at fault, hot water not able to reach downstairs rads? Could this apply to my boiler, i read that the circulation pump kicks in at least once per day even if the CH is not used? Would the boiler not register an error if the pump was not working correctly?? Any help you can offer would be greatly appreciated.

Kind Regards

Alan Craddock

Hi Alan how old is boiler? Is it weather comp? Or do u have room stat ? It maybe the 2 rooms are up to temp, or balancing is required or are there any restrictions in rad valves?if the pump is faulty you would be lucky to get 1 max of 2 rads working also if pump is faulty you would here it grinding or the boiler would go to overheat fault code f2 due to circulation problems,had this sort of report a few times and not had a pump issue,it may be a one off if it is the pump

 

[stevetheplumber]

probably trvs stuck down remove head and see if the pin can be depressed

 

[Clint 1979]

As Steve said, check the TRV's first......

 

[allybaba1975]

Sounds like sludge in the system, your best bet would be to get someone in to drain the system and see what colour the water is (black would indicate black oxide sludge, corrosion in the system), you may need to get your system flushed and possibly have a magnetic filter fitted whilst you're at it.
If your pump didnt work boiler wouldn't work (unless its noisy and slowing down), but if all the upstairs rads and 2 of 5 downstairs are getting hot i would say your circulating pump sounds ok!

Good luck

Thanks Clint for the reply. When I bled a couple of the downstairs rads, the water that came out was black. And the bottom of the rads that do heat up are cold, top of rads getting hotter. Does this also point to sludge?

Cheers Alan.

 

[allybaba1975]

Thanks both. Do I have to unscrew with the nurled steel part underneath the valve?

 

[kris]

Hi there allybaba . Defo try the trvs first and at least it will eliminate that. It's not uncommon for a few trvs to go but it is uncommon if they were workin couple days ago... Is your boiler upstairs by any chance. It might be gunk in the system or could be pump starting to fail. Is it a combi. What to do is close all the upstairs trvs and see if that makes a difference. If the trvs pins are stuck it won't but if rads heat up then you can eliminate trvs and put it down to a restriction or pump.

 

[allybaba1975]

Just checked first trv. Definetly seems stuck. Possible to release it? Or do I need to replace? Thanks for your feedback both.

 

[GasmanxxxR1]

use pliers to move pin up and down a few times to ease it

 

[kris]

Just checked first trv. Definetly seems stuck. Possible to release it? Or do I need to replace

. I sometimes put bit of squeezy or grease onto it as I'm sliding it in n out. Sometimes if there pressed right in you need to get hold with grips or pliers and gently pull out and gently tap valve with end of grips it sometimes helps free the spring... Gently does it.

 

[Clint 1979]

Hi Alan,
From what you have described it sounds like you have sludge in the system, but do as the other lads have said to eliminate the TRV's.
If the TRV's are working and the rads are still hot at the top and cold at the bottom then it's a restriction (sludge) and you will need to have the system flushed, if there is black water coming out of the bleed valves then having the system cleaned regardless of the TRV's would be a good idea.
It's possible to remove just the two rads that are causing the problem and flush them through independently of the system to get you running, but have the whole system cleaned if possible!

Hopefully though it will just be sticky TRV's and you can at least get the rads working.
As Kris said......GENTLY DOES IT!

 

[allybaba1975]

Hi,

Found the TRV on the rad in the hall stuck down. Released as suggested by Gasman in other post. Now getting hotter, hotter at top than bottom. Not as hot as the rads upstairs - Is this normal? Boiler is located in airing cupboard upstairs Other rad in kitchen - trv seems fine moving up and down freely, but still not getting warm at all. Any ideas ? Thanks all for your help so far.

Cheers Alan