Hot water but cold rads (HRM Wallstar 15/20)

[Cold of Cambs]

Hi there

New to the forum (first post). I've signed in as Cold of Cambs... for that is what I am.

I've had this problem once before and was told it was caused by low pressure. I now have a top-up valve which I use to ensure the boiler is at least 1bar when cold.

The firing cycle is regulated by a Danfoss programmable timer unit that has lights for both the radiators and the taps. The boiler fires fine, but only for the water from the taps, the boiler doesn't fire when the light comes on for the radiator.

I've tried bleeding the rads but they are all fine.

I would be most grateful for any advice, thanks

Cold of Cambridge

 

[Millsy 82]

Possibly 3 port valve, Stat or programmer

 

[Simon F]

try turning on the programmer for water and heating

ps-:welcome: along, hope your warm before to long

 

[SimonG]

Possiblyy pump. Hot water possibly on gravity. Does the boiler fire at all when you first switch the heating on, even for a short time?

 

[Simon F]

do you know if your set up is y plan/s plan?
one zone valve with 3 ports or two with 2
if none of the questions seem to be in your language then some pictures might help

 

[Cold of Cambs]

Thank you all for such very swift advice, I would have responded sooner but, alas, my fingers are too cold...

@Simon F - I see you have just landed from Holland, for you most definitely speak Dutch. If my plight continues for much longer however, I will do as you suggest and include some photos within this thread.

@Simon G - I'm liking the gravity/pump theory; how can I check this? No, the boiler does not fire (not even for a short time) when switched on to the rads

@Simon F - A good plan without doubt, unfortunately these run independent from each other so this option is not available (and if it were an option surely this would be a pyrrhic victory as the original fault would still be present). My thanks for your most warm welcome

@Millsy82 - (For one moment I thought it might have be compulsory to be a Simon within this thread). The stat seems to be fine and the programmer also seems to be working okay. Where do I find my 3 port valve (and what does it look like)?

 

[Cold of Cambs]

Thank you all for such very swift advice, I would have responded sooner but, alas, my fingers are too cold...

@Simon F - I see you have just landed from Holland, for you most definitely speak Dutch. If my plight continues for much longer however, I will do as you suggest and include some photos within this thread.

@Simon G - I'm liking the gravity/pump theory; how can I check this? No, the boiler does not fire (not even for a short time) when switched on to the rads

@Simon F - A good plan without doubt, unfortunately these run independent from each other so this option is not available (and if it were an option surely this would be a pyrrhic victory as the original fault would still be present).
My thanks for your most warm welcome

@Millsy82 - (For one moment I thought it might have be compulsory to be a Simon within this thread). The stat seems to be fine and the programmer also seems to be working okay. Where do I find my 3 port valve (and what does it look like)?

 

[scoullar]

sounds like zone valve to me either two or three port whatever change the head

 

[Cold of Cambs]

Hi Scoullar Thanks for the analysis. How much can I expect to pay for a new head plus labour and call out to fit it? (and what if it turns out to be the pump...? what do they cost?)

Thanks in advance!

 

[Millsy 82]

Its best to get somebody out to diagnose the fault. It usually takes a few minutes. It could still be a programmer or stat and a few little electrical checks and you will know for certain.