No heat upstairs, cannot locate CH pump, what to do

[Set Square]

The 50/15 is fine unless it's a *very* large house. Are you saying that the downstairs rads are not very hot either, or are they ok? What are the flow and return temperatures for them? [How are you measuring pipe temperatures?].

If the boiler is running at 80 but the rad inlet is only 57, there is a massive differential along the supply pipe - which means the flow is very small. This would suggest either a blockage, or a valve which isn't open enough. Have you exposed all the pipes which feed the upstairs circuit? It is possible that there is an anti-gravity valve - which is designed to stop gravity circulation when the pump isn't running. If this is jammed almost shut, it might explain your symptoms. It would be in the vertical supply pipe goint to the upstairs circuit.

[Tony]

The downstairs rads are very hot..

I lifted the floorboard upstairs which was above the pipes running down the landing, the pipe is very hot as the up pipe meets the long runner , but it soon cools down as it reaches the first spur in either direction.. Does this point to an obstruction in flow.. air I guess, if so whats the next step to flust it out..

I did stop the rad valves from leaking using boss & hemp, no more water leak when valve is set in between, it was previously ok when either full open or closed, but I worry that it may be drawing in air when pump is on, is that likely..?

I think that maybe I sould replace the valves sooner rather than later..

Meantime I want to get the damn hot water circulating through the rads..

.. Tony

[Dave Plowman (News)]

All the pump has to do is overcome the 'resistance' in the system. And all are suitable for the average house. FWIW, I've got a three story Victorian one - so the rads in the top floor are perhaps higher than most. But the pump is on the minimum setting.

If you've not got air in the system I'd reckon on some form of blockage.

Any work been done in the house recently where a pipe may have been crushed, etc?

[gastec]

ITs difficult to fault find on your system via the net but i would no listen to that set square chap as he obviously knows a little about c repairs....It could indeed be the pump....However there may be restriction or low water in your system.....did you get water as yo bled the upstairs rads....I bet your correct regards the pump....I hop you are...its an easy fix....

ps...even if the pump seems to be turning it may only be powerful enough to heat a few rad

-- gastec

[Set Square]

You've never given an explicit answer to my question about the small F&E tank has water in it. This is paramount!

Assuming it does (and remember this is the *small* tank not the large cold header tank) proceed as follows:

Go to each upstairs radiator in turn. Turn off one of the valves. Open the bleed screw, and bleed a couple of litres of water into a bowl. Open the valve which was closed, and close the other one. Repeat the bleeding operation. Open both valves. This should purge any air out of both the feed

*and* return pipes. [If you have both valves open when you bleed, you'll still get water out even if one pipe is blocked, or has an air-lock - hence the need to bleed with each valve open, in turn].

If they *still* don't get hot, repeat the exercise of turning off the downstairs rads, and having just one upstairs rad on at a time until it gets the idea!

[Tony]

Thanks for your persistance with me and my problem..

The small tank in the loft does have water in it , I held the float up with string and stick and bled a rad to see if the water level would fall, It did.. So I assume that its function is OK,

I'll go and bleed the rads as you instruct and report back, I take it that I should turn the circulation pump off whilst bleeding, I will anyhow..

.. Tony

[Set Square]

If you had bothered to keep up, you would know that he has already changed the pump to no avail - and is now following further sound advice - mercifully not yours!!

[chris French]

In message , gastec writes

From what I see he seems to have fair understanding.

He has already changed that.....

which is in discussion/investigation at the moment.....

He has already check the header tank...

He has already reported that he does....

He has already reported that it hasn't helped....

You know it would help if you bothered to read a thread first....

[Ed Sirett]

Is it possible that the downstairs valves were set to something other than fully open before you started work to stop the leaks?

It might be that you have an anti gravity valve in the feed to the upstairs rads which means the downstairs ones have to be restricted to balance the system.

The restriction is usually done by turning the lock sheild to down to about 1/2 turn open and further tweaks as needed.

[Ed Sirett]

The 50/15 should be OK for up to about 20kW (a largish house). My moneys on a balancing problems and/or an airlock. No on 2nd thought since you get some heat to the coolest rad, I'll say it likely is a balancing problem.

[Rob Morley]

Judging by your performance so far I know who I'd listen to.

[Tony]

Back to my problem......

I've uploaded a diagram of the boiler plumbing see what you think..

I was tracing the pipework I was drawn to a connection on the

22mm CH pipework, I've always thought that it was just a joint but on furthur investigation it appears to be a valve, it took a torch and a hand mirror to view the arrow and " TOP" markings at the very back of the valve, Now maybe this is the problem of the reduced flow to the upstairs rads. The very front of the valve as a small screw in it, which is as tight as I can get it but there is still a very small drip of water coming from it.. I feel a little stupid in not reconising the valve, as I said thought it was just joining two pipes together and that the screw was perhaps an earthing point..Does the screw have any function>

Is ther a way to test if the valve is faulty??

Ofcourse it could be a red herring,

.. Tony

[Set Square]

>> When I was tracing the pipework I was drawn to a connection on the

The valve is what several of us have been asking about when we said (is there an anti-gravity valve in the vertical pipe which feeds the upstairs circuit?" - remember?

This is most likely the cause of your woes. From your diagram, it is obvious that you have a gravity HW and pumped CH system. In such systems, the upstairs radiators sometimes get hot due to gravity circulation when they shouldn't (i.e. when the pump isn't on in response to a CH demand). The anti gravity valve is a check valve, with a little weighted flap, which requires a slight pressure to open it. The pump generates enough pressure to open it - but convection doesn't.

For one reason or another, this valve isn't opening properly to allow flow to the upstairs radiators. The most likely reason is that it is gummed up inside - and needs replacing. There is an outside chance that someone has turned the pump round to pump in the opposite direction - thus swapping flow and return pipes - but that is unlikely. Make sure it's in the flow pipe rather than the return. [It looks like it is, from your diagram, provided the pump direction is as shown]. So my money's on the valve being seized up. It needs junking, anyway, if it's leaking.

[Tony]

Just a quickie , to say thanks for all the help in sorting out my little problem. Its was indeed the anti-gravity valve, I've this afternoon replaced it and now I have nice hot rads ALL around the house..

Sorry to drag it on a bit, the valve wasn't visually obvious..

.. Tony