hW not heating

diggerdigger

Hi, I'm in a v old house, which has had some zoning done to it. But as far as I can make out, the top floor zone heat goes to the HW cylinder.

Now every rad in the zone has been bled, and heat thoroughly. The tank though, does not heat at all.

I've played with the valves to try and get something, but there's no heat at all.

The airlock valve was opened, and only a little air escaped.

I've remove the temp sensor from the tank.

Anyone have any ideas what I could try next.

K.Flyer

Move the white plastic valve in pic 1 so the number 6 is in line with the arrow position and see if that helps anything.

Wearb

K.Flyer wrote: »

Move the white plastic valve in pic 1 so the number 6 is in line with the arrow position and see if that helps anything.

And perhaps put the temperature sensor back on the tank ?

diggerdigger

K.Flyer wrote: »

Move the white plastic valve in pic 1 so the number 6 is in line with the arrow position and see if that helps anything.

I've moved the thermostatic valve and replaced the temp sensor on the tank, and still nothing.

All the pipes leading to the coil are stone cold. What does the second white valve do, is that the cylinder balancing valve?

Wearb

Normally with zoning work you would have 3 done. Upstairs, downstairs and dhw. Is that what you have?

Wearb

Also, where is your cylinder in relation to your upstairs rads?

diggerdigger

Wearb wrote: »

Also, where is your cylinder in relation to your upstairs rads?

It's a really old house. Gun barrel heating distribution that's been modified to 2 zones. As far as I can make out, there is no separate hw zone. The system also used to be gravity fed, with 2 obsolete tanks in the attic. Now seems sealed. 2 condensing boilers in parallel.

The cylinder is at the tip top of house, at the same level as one other rad. That rad is piping hot. Boilers are 3.5 stories below.

System is well pumped, with 2 pumps at boilers, and 2 pumps on zone returns. Airlocks cleared afaik, and pressure seems good at 1.5.

Wearb

Could your coil be airlocked? Is the tank cold where that temperature probe from first pic reads the cylinder temperature.

diggerdigger

Wearb wrote: »

Could your coil be airlocked? Is the tank cold where that temperature probe from first pic reads the cylinder temperature.

I guess it could be. The tank is stone cold. How would I check coil for airlock?

Wearb

diggerdigger wrote: »

I guess it could be. The tank is stone cold. How would I check coil for airlock?

There should be a bleed point or automatic bleed at the highest point on the system. Is there any heating pipework higher than the top connection point of the coil?
If there isn’t then you could crack open the top joint of the coil to see if air or water comes out there.. Be careful if you attempt this. It wouldn’t be the first time that someone allowed the coil pipe to twist inside the cylinder and ruined it.

diggerdigger

Wearb wrote: »

There should be a bleed point or automatic bleed at the highest point on the system. Is there any heating pipework higher than the top connection point of the coil?
If there isn’t then you could crack open the top joint of the coil to see if air or water comes out there.. Be careful if you attempt this. It wouldn’t be the first time that someone allowed the coil pipe to twist inside the cylinder and ruined it.

There is an automatic bleed valve. A little air escaped when I opened the cap at the start when I was bleeding the rads, but really just a puff. Cap is off now.

Man this is wrecking my head.

Wearb

If you answer ALL my questions I will try to help.
I saw the pic of the aav, but I’ve no idea where it is in relation to the rest of the cylinder pipe work.

agusta

diggerdigger wrote: »

There is an automatic bleed valve. A little air escaped when I opened the cap at the start when I was bleeding the rads, but really just a puff. Cap is off now.

Man this is wrecking my head.[/QUOT
Turn off all the other rads manually and then see what you get at the cylinder

diggerdigger

Wearb wrote: »

If you answer ALL my questions I will try to help.
I saw the pic of the aav, but I’ve no idea where it is in relation to the rest of the cylinder pipe work.

Hi, sorry, it's about 3ft above the top of the coil.

Wearb

diggerdigger wrote: »

Hi, sorry, it's about 3ft above the top of the coil.

Is it tee’d off where the pipe enters the top part of the coil?

Did you give Agusta’s Suggestion a try?

diggerdigger

agusta wrote: »

Turn off all the other rads manually and then see what you get at the cylinder

After about 10-15 minutes the boilers seem satisfied with the return temp and stand by.

So nothing different at the cylinder.

diggerdigger

Wearb wrote: »

Is it tee’d off where the pipe enters the top part of the coil?

Did you give Agusta’s Suggestion a try?

Yep, it's teed off the top of the coil. Tried Augusta's suggestion and the boilers go to standby.

diggerdigger

diggerdigger wrote: »

Yep, it's teed off the top of the coil. Tried Augusta's suggestion and the boilers go to standby.

Put a couple of rads back on, and it seems to be getting a *little* heat.

Wearb

diggerdigger wrote: »

Yep, it's teed off the top of the coil. Tried Augusta's suggestion and the boilers go to standby.

It is unlikely to be an airlock in the coil then.
There must be some sort of obstacle to the normal flow, whether that be a broken valve, accidentally closed valve or gunk, it might need experienced eyes on the system.

rightjob!

Take the white head completely off the valve at the coil,it twists off and see is the pin fully in or out,
Did you mess with the bypass valve?

diggerdigger

rightjob! wrote: »

Take the white head completely off the valve at the coil,it twists off and see is the pin fully in or out,
Did you mess with the bypass valve?

Took the thermostat head off, and it seemed to gurgle a little. Doesn't seem fully in. Seems fully out. I pushed it a few times and maybe came out a little. But I could be imagining at this stage.

Is the bypass valve the valve that bridges the pipes that enters and leaves the coil? I have messed with that. I fully opened. I fully closed and the step by step opened. But only when tank not heating. Didn't seem to make a difference at that time.

rightjob!

diggerdigger wrote: »

Took the thermostat head off, and it seemed to gurgle a little. Doesn't seem fully in. Seems fully out. I pushed it a few times and maybe came out a little. But I could be imagining at this stage.

Is the bypass valve the valve that bridges the pipes that enters and leaves the coil? I have messed with that. I fully opened. I fully closed and the step by step opened. But only when tank not heating. Didn't seem to make a difference at that time.

Any photos of pipework under the boiler?zone valves ect?

diggerdigger

rightjob! wrote: »

Any photos of pipework under the boiler?zone valves ect?

As it currently stands. Seems to be some heat entering the top of the tank with the thermostat valve off. But also I only have about 10 of 30 rads on.

diggerdigger

diggerdigger wrote: »

As it currently stands. Seems to be some heat entering the top of the tank with the thermostat valve off. But also I only have about 10 of 30 rads on.

I mean the thermostat head off. Valve fully open.

rightjob!

diggerdigger wrote: »

As it currently stands. Seems to be some heat entering the top of the tank with the thermostat valve off. But also I only have about 10 of 30 rads on.

Any of the actual gas/oil boiler?and the zone valves

diggerdigger

rightjob! wrote: »

Any of the actual gas/oil boiler?and the zone valves

Sorry. Misunderstood. Hard to get in one pic. 2 boilers in parallel in a separate room from zone valves. Both boilers have integral pumps also.

Motorised Valves and pumps on return of 2 upper zones.

3rd zone is basement where boilers and pipework is. HW cylinder is 3.5 stories up on one of the zones.

Zoning is really just for pumping, there is no individual control of zones on or off, just thermostats on the rads.

rightjob!

diggerdigger wrote: »

Sorry. Misunderstood. Hard to get in one pic. 2 boilers in parallel in a separate room from zone valves. Both boilers have integral pumps also.

Motorised Valves and pumps on return of 2 upper zones.

3rd zone is basement where boilers and pipework is. HW cylinder is 3.5 stories up on one of the zones.

Zoning is really just for pumping, there is no individual control of zones on or off, just thermostats on the rads.

Its either a zone valve closed or else a pump gone thats my guess

diggerdigger

rightjob! wrote: »

Its either a zone valve closed or else a pump gone thats my guess

All the rads in the zone heat up great - get red hot. Pumps and valve seem to function ok. Doesn't make much sense. Minds melted with it.