Boiler won't come on unless triggerd by cylinder thermostat

[swbjackson]

The left hand pump is the HW pump the right is the heating pump. I think that the relay shown in the diagram is incorporated in the box on top of the HW pump. I would guess that the relay has failed. Guessing at the age of the system I'm not sure you will be able to get any spares. It could be possible to wire an external relay to get it going.

 

[clf-gas]

Namsag, is that the nonreturn under the the gold ciculator.

So, the flow is from the left of blue, DWH from top and heating to right.
Does it act like a port valve buy restricting flow to cyl when not called for

 

[clf-gas]

Double click

 

[keshdevon]

This is what is behind the black junction box

[GALLERY=media, 8226][/GALLERY]

 

[namsag]

Yeah thats that non return valve Basically the HW pump(blue) is not strong enough to open it then when the gold coes on as well it opens it.

SWB the relay is usually in a grey box elswhere , It definetly is not in the blue pump

 

[keshdevon]

Top exit from blue pump goes into the hot water cylinder.
Right hand side exit from gold pump disappears off somewhere below the airing cupboard.

Gold pump makes a gentle hum, and if I press it slightly it touches the back wall of the airing cupboard and vibrates slightly. So it is working right?

I don't think I am up to wiring in an external cylinder. I will just have to keep wasting more hot water to trigger the system - or take more baths!

I really cant see the point in spending money on an engineer to fix it for me if I am going to replace it.

 

[keshdevon]

The blue pump has a numbered dial or sorts on its side. Currently its at 3. Might turning it up to 5 (max) provide enough flow to open the non return valve?

 

[namsag]

Kesh. I edited a previous answer just take the cylinder stat off and lay it on the floor that way it will never get satisfied and will allow you heating.
Just be careful as water will be hot when you use it or keep boiler stat down low

 

[keshdevon]

Thanks samsag. I will try that.
Thanks very much for your suggestion. I will let you know if it works!

 

[keshdevon]

sorry didn't mean to spell your name wrong namsag!

 

[clf-gas]

Kesh. I edited a previous answer just take the cylinder stat off and lay it on the floor that way it will never get satisfied and will allow you heating.
Just be careful as water will be hot when you use it or keep boiler stat down low

So, when cylinder is satisfied and heating is called do you still get some flow through cyl coil.

 

[namsag]

No worries it could have been worse ie bawbag

 

[keshdevon]

Its working. The radiators and boiler are staying on.
THanks to everyone for their help and trying to figure out what was going wrong. At least I can stay a bit warmer now, so Im a happy girl.
Roll on spring when I can get the whole lot replaced.

Thanks again, from a soggy Devon. No snow where I am!