Cold downstairs radiators.

[MickBrown]

This is a large house with 9 radiators upstairs and 10 radiators downstairs. I changed some radiators here about a year ago and had no problems refilling (vented system) and no airlocks. Suddenly the downstairs radiators have stopped working. Five of the radiators are fed under the floor from the boiler room and the others have drop down pipes from above in 4 different areas. I thought initially the pump but it appears to be working, I switched off the upstairs radiators and all the downstairs radiators except one of those fed from under the floor. I managed to get heat through this one but the further away from the boiler room the under floor piped radiators would only get luke warm or not heat at all. The ones with the drop down pipes would only get hot when I bled off water but stayed hot, although not sure yet if they stayed hot when the upstairs radiators are turned back on as the lady wanted to keep the downstairs ones hot for a meeting that evening. Will find out today what happened. The hot water pipes and the heating pipes have separate pumps which are both the same type. Next time I go I will change the pumps over to see if what happens. Would you guys suspect the pump has failed even though it appears to be working?

 

[Whn1]

Sounds like a big system, how many zones are there?

 

[Whn1]

Does sound like a pumping issue.

 

[MickBrown]

Sounds like a big system, how many zones are there?

It is all one big zone. It is a very old house.

 

[Whn1]

Two pumps? How are these set up? Do you mean there's one for secondary hw?

 

[MickBrown]

Yes there is a secondary circuit just for hot water. There are pipes and a pump one side of the boiler for heating and pipes and pump the other side for hot water.

 

[tom609]

Does sound like a pumping issue.

i agree pump issue do you have a room stat if so do you have one upstairs and downstairs could be a motorised valve problem

 

[Whn1]

It's one zone, so one stat. Are both pump heating circulator pumps or is the hw one a bronze one?

 

[Whn1]

Shut both pumps down, swap them over and see if that cures it, that's a quick enough test.

 

[MickBrown]

There is no room stat, I have only found one motorised valve and that is on the HW circuit just by the hot water cylinder. All the radiators have thermostatic valves. I plan to change over the pumps, both pumps are exactly the same. Hopefully this will cure the problem and prove it is a pump issue.

 

[Destroyer2813]

If one pump is running secondary hot water changing that one isn't gonna solve your heating issue

 

[Whn1]

I Ment change it temp to see if it solves the problemos, if so new pump.

 

[tom609]

seems to me he has a pump on the heating circuit and a pump on the primarys to the cyl so by changing the primary one to the heating circuit providing its working ok should give him heating on the g floor i would just change the heating pump to much faffing about if it works great if not that taken out ouf the e quasion

 

[Dan Masey]

If he swaps pumps, won't he then get heating crap into his hot water? Or would it not matter much as only a short test??

 

[tom609]

no it doesnt mix and both same pumps he said so i guess both steel pumps

 

[Whn1]

If he swaps pumps, won't he then get heating crap into his hot water? Or would it not matter much as only a short test??

Won't hurt too much dan.

 

[Whn1]

Doubt they'll both be steel pumps, expensive way to do things.

Think there is some confusion going on.

 

[tom609]

why do you think that could be 2 grunfos 15/50 iam assuming the pumps are on the heating circuit and the hot water primarys from the boiler unusual but hey ho

 

[Whn1]

Yea, hard to workout, don't know if there's a pump on the primary's for the hw which I doubt. Or a pump running secondary hw? Don't think the op is too sure himself.

Regardless just swap em and test if it works...

Myhead hurts

 

[tom609]

he did say both pumps were the same so doubt two bronze pumps come on england

 

[MickBrown]

Both pumps are Grundfos 15/60. The hot water cylinder is quite a distance from the boiler and so the primary circuit to that is pumped. There is a cylinder stat and timer and a motorised 2 port valve. The heating circuit is pumped and just has a timer and no other controls that I have found so far.

 

[stevetheplumber]

not that unusual on a large system to have two pumps each controlled seperately for heating and hot water the motorised valve was probably added as the hot water pump was pushing down the heating or just to use the microswitch in the valve as a relay as already said try swopping the pumps heat upstairs and not down is classic pump failure symptoms as upstairs will gravitate im betting on an old cast boiler being in the system