Radiators are on but no hot water

crawlb4uwalk

The central heating is coming on as usual, radiators are hot (bathroom radiator needs to be bled but that is not unusual, I do that twice a month or so) All the lights on the boiler are on. All digits on the panel are correct. The pipes coming from the back of the boiler are hot. There is a pump at the bottom, the pipes both sides of the pump are hot.

None of the pipes in the hotpress are hot.

The immersion works fine.

What could be wrong?

shane0007

Oil, gas, solid fuel, or mixture?
System zoned with zone valves or not?
Is problem only just happened or on-going?

More info please?

crawlb4uwalk

shane0007 wrote: »

Oil, gas, solid fuel, or mixture?
System zoned with zone valves or not?
Is problem only just happened or on-going?

More info please?

Its a wood pellet burner. There are valves but I know nothing about them, never had to touch them. This is the first time this has happened. There was a storm a few days ago and the lights flickered a few times...very small power outage. But the boiler had no problems and is still heating rads.

shane0007

You probably have a motorised valve on the DHW circuit. This will be an electrical valve on a heating pipe but it could be located at the boiler or in the hot press. Depending on the make, it should have a manual slider to put it in the manual position.

crawlb4uwalk

shane0007 wrote: »

You probably have a motorised valve on the DHW circuit. This will be an electrical valve on a heating pipe but it could be located at the boiler or in the hot press. Depending on the make, it should have a manual slider to put it in the manual position.

theres an electrical valve on the floor of the hotpress. theres a small lever currently set to AUTO, there is a MANUAL option. Is this what you are referring to?

Thanks!!

shane0007

Yes, if it is on a pipe either coming from the coil of the cylinder or going to the coil of the cylinder.

Slide to manual. Have heating on & see if heat is now passing the valve.

crawlb4uwalk

shane0007 wrote: »

Yes, if it is on a pipe either coming from the coil of the cylinder or going to the coil of the cylinder.

Slide to manual. Have heating on & see if heat is now passing the valve.

Pipes are now hot going to the top of the cylinder. Is it safe to leave this on MANUAL?

shane0007

Yes but make sure it is not firing the boiler. It depends on how it is wired. You could also take the head off it & align the paddle in the open position & it will heat whenever the boiler heats the rads.

What make valve is it? Nearly all can be replaced with new heads so an easy fix.

crawlb4uwalk

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Not sure about the make... Here's some photos.

shane0007 wrote: »

Yes but make sure it is not firing the boiler. It depends on how it is wired. You could also take the head off it & align the paddle in the open position & it will heat whenever the boiler heats the rads.

What make valve is it? Nearly all can be replaced with new heads so an easy fix.

shane0007

Pulsar. They are gone bust but Chadwicks have taken over all their stock. Replacement available there. Sh1te quality though but without draining the system, a cheap & easy fix by sticking with the Pulsar.

crawlb4uwalk

shane0007 wrote: »

Pulsar. They are gone bust but Chadwicks have taken over all their stock. Replacement available there. Sh1te quality though but without draining the system, a cheap & easy fix by sticking with the Pulsar.

Great thanks for that. I'll keep an eye on it. Do you think if I put it back to AUTO it will stop heating the water again? I don't want it to over heat... Could that happen?

shane0007

Yes it will stop heating the water in Auto mode. The motor in the valve is most likely kaput. You can buy replacement motors at a fraction of the cost of the valve also but usually from the UK.
In Manual position it will be perfectly safe.

shane0007

If it is wired incorrectly you may find the valve is permanently on and this has burnt the motor out.

crawlb4uwalk

shane0007 wrote: »

If it is wired incorrectly you may find the valve is permanently on and this has burnt the motor out.

It's been there since about 2005, would it have burnt out by now if it was wired incorrectly?
I will leave it on manual. Thanks for the info.

crawlb4uwalk

@shane0007
Further to the water not heating (while raditors were getting hot) now the raditors are only getting lukewarm. the boiler is firing up but goes on standby and thinks that the water temperature has been met so all starts to cool down again. only some raditors get warm as the ones on the end of the line don't get any heat. Water is not hot in cylinder either.

Thoughts?

shane0007

Sounds like a circulation issue. If both are not heating properly and the boiler is at temperature, it sounds like the circulating pump has had it or it is pumping weak. Replacement pump would be my guess.

Irish Steve

Some strange symptoms here, Wondering if the pump is powered in a strange way via the MV, and for some reason it's now not running.

You mentioned a storm and a power outage, That might have blown something. Are you any good with a multimeter, and is there an easy point to get a safe access to the power connection for the pump. Might be worth checking to see if there is power to the pump at any stage. If there is a microswitch in the MV, there may be a problem with it not working, or not getting actuated for some reason in manual mode, so it may not be sending the right information back to the other devices.

Also might be worth checking if there is a capacitor on the pump, if there is and its failed, the pump may not be starting up correctly, and that should be replaceable without having to remove the pump. If in doubt, google is your friend, central heating pump capacitor should point you in the right direction. That said, if it is the capacitor, depending on where you are, it may be as cheap to replace the pump completely rather than spend a lot of time searching for the right capacitor, it will depend on where you are and what local facilities are like.

I'd also be slightly concerned that you are having to bleed a radiator on a regular basis, that suggests something strange is happening, but determining what that is may take some work.

The failed MV is certainly a factor, its possible that sorting this out so that it works correctly may resolve the other problem issues. Another thought in passing, the Manual position on an MV is not fully open to water flow, it's normally only open enough to operate the micro switch (where fitted) and allow enough flow through the valve for air in the line to be expelled. Could be that if the boiler is high capacity, the valve is not open enough in manual to allow enough flow to keep the boiler happy.

Dtp79

crawlb4uwalk wrote: »

@shane0007
Further to the water not heating (while raditors were getting hot) now the raditors are only getting lukewarm. the boiler is firing up but goes on standby and thinks that the water temperature has been met so all starts to cool down again. only some raditors get warm as the ones on the end of the line don't get any heat. Water is not hot in cylinder either.

Thoughts?

Is it open vented or a sealed system?

crawlb4uwalk

Tried it this morning. Boiler works fine until the pump kicks in then the boiler starts to power down again. Pump stays stone cold so going to assume at this stage the pump is bust. I doubt I'll get one over the weekend.

Any idea if anywhere in Galway city are open Sundays... Walshs on the Tuam road would hardly be open?

shane0007

crawlb4uwalk wrote: »

Tried it this morning. Boiler works fine until the pump kicks in then the boiler starts to power down again. Pump stays stone cold so going to assume at this stage the pump is bust. I doubt I'll get one over the weekend.

Any idea if anywhere in Galway city are open Sundays... Walshs on the Tuam road would hardly be open?

Get a decent brand such as a Grundfos @ don't under-size it.

crawlb4uwalk

Its a Grundfos thats on it. I'll try get the same.

shane0007

crawlb4uwalk wrote: »

Its a Grundfos thats on it. I'll try get the same.

Yes but just are still under-sized. Generally they are 25/50's installed but most require a 25/60 especially if you have a three zone system.

crawlb4uwalk

shane0007 wrote: »

Yes but just are still under-sized. Generally they are 25/50's installed but most require a 25/60 especially if you have a three zone system.

just looking at it now, its a 15/50... Probably not so good? What would I be looking at paying for a 25/60 ?

shane0007

crawlb4uwalk wrote: »

just looking at it now, its a 15/50... Probably not so good? What would I be looking at paying for a 25/60 ?

€130 including vat
They are doing specials at the moment on Grundfos 25/60 Alpha pumps. They are modulating.

crawlb4uwalk

shane0007 wrote: »

€130 including vat
They are doing specials at the moment on Grundfos 25/60 Alpha pumps. They are modulating.

Whos doing them?

just found this... http://www.heatingboilerspares.com/PumpGrundfosCirculatingUPS256013059997378incvat.htm

shane0007

crawlb4uwalk wrote: »

Whos doing them?

just found this... http://www.heatingboilerspares.com/PumpGrundfosCirculatingUPS256013059997378incvat.htm

Price I quoted would be from Chadwicks or Heatmerchants.
That link is for an OEM Grundfos pump & is a good price. Nothing wrong with it. Check delivery price.

crawlb4uwalk

shane0007 wrote: »

Price I quoted would be from Chadwicks or Heatmerchants.
That link is for an OEM Grundfos pump & is a good price. Nothing wrong with it. Check delivery price.

Just an quick update - while it was Sunday and nowhere was open to look for a pump I opened up the boiler to clean it while its cold. There's a bit of opening and parts to it, baffles and plates etc but low and behold there was a part of the fibreboard panel in the bottom has cracked in half and laying on the ash pan.

I've attached the cross section of the burner. The red square is the bit thats broken/gone. I would assume by the arrows showing the direction of the heat that it now comes back down the other side of 'part B' , if it gets that far, and doesn't reach the top before it comes back down passed the 'red' fibreboard panel.

Going to see if I can get a bit of that board tomorrow.