Heating OK but No Hot Water

[seco services]

bleed it with the hw off so pump etc is not running.

if still no air released try it on speed 3 and see if the bottom pipe gets hot.
it sounds just like a airlocked cylinder coil.

 

[dcaraher]

bleed it with the hw off so pump etc is not running.

if still no air released try it on speed 3 and see if the bottom pipe gets hot.
it sounds just like a airlocked cylinder coil.

Seco thanks for the continuing help.

In summary:

1. Make sure the timer is not set to HW
2. This should stop the pump (If the timer is set for CH does this cause the pump to kick in?)
3. try to vent the cylinder again. if no air out try pump on speed 3.

It souns as though I should have some air coming out of the vent is that correct?

 

[seco services]

you'll need heating off as well at the moment. either stat down or off at programmer.

if pumps running it will try to push air down but air only rises so turn all off and the air should rise to the vent area.

yes useally hot pipe in cold out indicates a airlocked cylinder coil there are a number of ways to remove it.

yes so you want any trapped air to release out of the vent. sometimes can take a min or two to release.
stick an old towel under vent or dish.

 

[dcaraher]

you'll need heating off as well at the moment. either stat down or off at programmer.

if pumps running it will try to push air down but air only rises so turn all off and the air should rise to the vent area.

yes useally hot pipe in cold out indicates a airlocked cylinder coil there are a number of ways to remove it.

yes so you want any trapped air to release out of the vent. sometimes can take a min or two to release.
stick an old towel under vent or dish.

Once again many thanks. I'm just off to pay a visit to the loft. If you are still around when I get down I will send an update. Wish me luck

 

[seco services]

loft whats in the loft ?

 

[dcaraher]

loft whats in the loft ?

Just come down from the loft. The cylinder is in the loft and the vent I was describing is just above the thermostat control on the feed into the cylinder. The name on thew vent was Flameno varivent. I unscrewed the red dust cap and loosened the vent I did get some air out, not much. I have just put the HW and CH back on with the pump on setting 3 to see if anything has changed.

Was I in the wrong area?

 

[seco services]

no didn't know cylinder was in loft turn heating off only hw on as i want all flow through the cylinder to force the water round.
and make sure the cylinder stat is calling for heat and pump/boiler are running.

tell me if the bottom pipe starts getting hot.

 

[dcaraher]

no didn't know cylinder was in loft turn heating off only hw on as i want all flow through the cylinder to force the water round.
and make sure the cylinder stat is calling for heat and pump/boiler are running.

tell me if the bottom pipe starts getting hot.

I have a very hot pipe before the thermostat, a very hot pipe into the cylinder but a cold pipe below that coming out.

I'm with you on this one it does sound like an air blockage somewhere. Is there anything else I can try?

 

[seco services]

you don't happen to have a pic of the cylinder pipework etc ?

was the system drained when the valve was changed ?

 

[dcaraher]

you don't happen to have a pic of the cylinder pipework etc ?

was the system drained when the valve was changed ?

Not good pictures but here goes:

I didn't drain the system because I only changed the head.[/img][/url]

 

[seco services]

i take it that the pipe out the bottom is quite a long horizontal before dropping down.

what is the thermostatic valve set at ?

 

[dcaraher]

i take it that the pipe out the bottom is quite a long horizontal before dropping down.

what is the thermostatic valve set at ?

In the first picture both sides of the Thermostatic valve are very hot. The bottom pipe runs away for some 5 meteres before dropping down, and is cold.

The thermostatic valve is set at 12, the highest setting.

The second picture shows what I think is the vent valve .

 

[seco services]

on that bottom pipe cylinder return is their any compression joints etc that you can slacken ?
i would say the airlock is their and 5 m is along horizontal run.

 

[dcaraher]

on that bottom pipe cylinder return is their any compression joints etc that you can slacken ?
i would say the airlock is their and 5 m is along horizontal run.

I think we are getting closer to the root cause. The bottom pipe out of the cylinder is cold bu only for about 18 inches, it then comes to a T junction, soldered junction, which goes off to a red "expansion tank???" and then continues on its run. It also goes off to another valve. I have tried to get a picture of this, see below. After this cold section of about 18 inches the rest of the pipe is hot.

As you look at the picture the bottom right is the other valve I refer to and you can see what I think is an expansion tank at the top of the picture

 

[seco services]

if its on only hw at programmer your boiler must be shutting down as the cylinder is not circulating.
where is the hot pipework coming from is that the return where you had the heating on earlyer ?
the only other option i can see is slacken the nut on the base of the cylinder return.

when did this decide to happen before you mucked about or is this the original fault and not the valve ?