It is currently 29 Mar 2024, 06:07
Deejay wrote:Morning Roger
I'd forgotten that you were using the heat store. I assume that it's a fully pumped system.
It does seem to be an airlock problem doesn't it. Do you know if the system ever worked properly?
Deejay wrote:The worst case scenario seems to be poor installation of the heating mains.
Deejay wrote:Before you take up the floors to check,
Deejay wrote:..... There is now a lot of live water in the system, full of air, which will take time to come out.
Bleed everything again. Keep bleeding every day to see if you can eliminate the air. You'll soon find out if most of the air collects in a particular radiator, which would help with locating airlocks.
Cheers
Dave
Robert wrote:So is this still a case of very low flow?
I know air is the main suspect but just wondering if there is a blockage somewhere?
You are re-using the existing heat store but is there lots of old pipe too or all new? I used to have a simple mesh filter in the return pipe to the boiler (fitted by the boiler installer) and it took no time at all to become blocked and need cleaning. I'm guessing you must have a proper magnetic filter (as I now have) but is it still clean?
Which reminds me it is probably time I cleaned mine again.
Are all your rads the same make? Any chance they are restricting flow?
Could there be some lump of crud in the pipe and you move it when you 'power bleed' then it drifts back to block somewhere?
9fingers wrote:Not sure I understand why a bleed valve presents a block in the system?
.....
Bob
RogerS wrote:
The tiny outlet in the bleed valve gives a high-impedance (for want of a better term) and if there is not enough head in the system then it wont flow out that easily. Want you need here is a good whoosh to get it all flowing nicely and to carry the air out.
It is that bad that even with the hosepipe connected there is sometimes no flow even then. You have to fit a suction device on the end of the hose to draw the water/air out.
Deejay wrote:Morning Roger
Am I right in assuming that the direction of the flow is down to the heating circuits?
Cheers
Dave
Robert wrote:You've confused me with your drawing
The photo above labelled neutral point shows a pump with vertical pipes and doesn't look like the pump could be left sitting in air.
Your drawing however shows a pump that is bound to sit in any air in the pipe and therefore pump nothing.
Do you have 2 pumps?
And even with your additional reading I still can't see how air can stop heating flow if the pump is powerful enough to overcome any head - which I'm sure it would be.
RogerS wrote:Deejay wrote:Morning Roger
Am I right in assuming that the direction of the flow is down to the heating circuits?
Cheers
Dave
Don't follow you, Dave
Deejay wrote:RogerS wrote:Deejay wrote:Morning Roger
Am I right in assuming that the direction of the flow is down to the heating circuits?
Cheers
Dave
Don't follow you, Dave
Does the arrow on the pump point downwards?
Robert wrote:If the flow is downwards...Your sketch shows flow to the pump input but there are 2 pipes (3 including what I guess is the fill pipe) going to the input in the photo. What are those pipes?
If it was pumped return it makes more sense as the heating and cylinder returns would come together.
The pump is the right way round?
Deejay wrote:Morning all
Roger
I think you mentioned that the DHW cylinder originally had separate flow and return pipes. (I can't find it in this post, hence the edit) Yes they did
Was the HW circuit pumped or gravity fed? pumped I've never fitted a gravity fed HWC but I think they had a non return valve in the circuit to stop heat escaping back down to the boiler. I think they also used a thermostat in the return (?) pipe to stop the flow when up to temperature.
Since you are reusing the old DHW piping, could there be anything left in the pipe work? No flushed out
Is there a non-return valve fitted in the new circuit from the heat store?No
Is that a new self regulating pump? Ni idea. Grundfos USP2 15/60If so, can you override it and set the speed to continuous until you sort out the airlock? I just have three speed settings
Cheers
Dave
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