I've had the programmer set to hot water only since it's been warm and
since yesterday morning, we've had no hot water. When I say no hot
water, it's very lukewarm.

So I thought I wonder if the motorised valve is faulty?? I set the
programmer to both heating & water and it had not made any difference.
The radiators is just luke warm too.

The pump is working ok (I only replaced this less than 2 years ago)
The motorised valve must be ok (Again I only replaced this less than 2
years ago).

The boiler does fire up and heats but only for 10 mins maximum before
it shuts down again.

I replaced the thermocouple was replaced approx. 6 months ago, when the
pilot light would not stay lit.

I then wondered if there is 'air' in the system or some leak? I've bled
all the radiators and thats was all ok. Checked the header tank and
plenty of water in there.

I am guessing that it could be either the boiler thermostat that is
faulty or could it be a more serious problem, like the heat exhanger??
It's a Thorn Apollo 30/50B - an older boiler that needs replacing but
it will have to wait until it's a must.

Anyway - any ideas what it could be before I call the heating engineer
out??

Look forward to your replies

blister72

The pump is working ok (I only replaced this less than 2 years ago)
The motorised valve must be ok (Again I only replaced this less than 2
years ago).

Could you explain these statements. Why must the pump and motorised valve be
OK?

Christian.

"Christian McArdle" wrote in message
. net...
The pump is working ok (I only replaced this less than 2 years ago)
The motorised valve must be ok (Again I only replaced this less than 2
years ago).

Could you explain these statements. Why must the pump and motorised valve
be
OK?

Quite. Many years ago I thought I had identified an intermittent ignition
fault in the capacitor in my car distributor. Bought a new capacitor, tried
it, fault still there. Bugger. about a day later, having removed bits of
wiring loom, dashboards etc., I tried another capacitor out of someone
else's car. Problem went. Replacement I had bought was faulty. Grrr. I was
unable to take it back to the shop as I had reduced it to a two-dimensional
object with a 2lb lump hammer.

Bob Mannix

The motorised valve works ok as

1) I can see the lever move automatically when I select water &
heating, from water.
2) both rads and water are lukewarm.

Motorised valve is fairly new - it was replaced not so long ago because
I could not have hot water without the heating being on!

The pump is working ok as

1) When I select different speeds, I can hear and feel the pump running
at different speeds. I can also feel the water gushing up the pipes,
particulary when I change from low speed to fast.


Perhaps I could be wrong, I accept that new (or fairly new parts) can
go faulty at any time. Is there a better way of checking??

blister72


Christian McArdle wrote:
The pump is working ok (I only replaced this less than 2 years ago)
The motorised valve must be ok (Again I only replaced this less than 2
years ago).

Could you explain these statements. Why must the pump and motorised valve be
OK?

Christian.

Perhaps I could be wrong, I accept that new (or fairly new parts) can
go faulty at any time. Is there a better way of checking??

I was just checking that you weren't eliminating the components on the basis
of installed time...

Christian.

"blister72" wrote in news:1122044859.947705.142380
@g49g2000cwa.googlegroups.com:

I then wondered if there is 'air' in the system or some leak? I've bled
all the radiators and thats was all ok. Checked the header tank and
plenty of water in there.


Have you bled the air from the system bleed valve too? usually it'll be
near the pump, valve, etc (in the airing cupboard) and will be a length of
copper pipe sticking up out of the system with a bleed valve on top. It'll
be higher than the pump, valve and coil.

Rich

--
Rich P
Replace .invalid with .com to reply.

Yep, I did that too - there was no air in the heating system
whatsoever.

blister72


Richard Polhill wrote:
"blister72" wrote in news:1122044859.947705.142380
@g49g2000cwa.googlegroups.com:

I then wondered if there is 'air' in the system or some leak? I've bled
all the radiators and thats was all ok. Checked the header tank and
plenty of water in there.


Have you bled the air from the system bleed valve too? usually it'll be
near the pump, valve, etc (in the airing cupboard) and will be a length of
copper pipe sticking up out of the system with a bleed valve on top. It'll
be higher than the pump, valve and coil.

Rich

--
Rich P
Replace .invalid with .com to reply.

I've done a bit more investigating this morning.....

The boiler fires up when I switch the heating and water on.
The cold entry pipe into the boiler is cold, as it should be.
The hot water pipe from the boiler is lukewarm.
The boiler itself is hot but not very hot as it usually is.

After about 5 minutes, the boiler then shuts down.

I am now wondering if there is an airlock in the boiler itself????

The cold entry pipe has a drain cock but there isn't one on the hot
pipe. I wouldn't be able to get rid of the airlock by draining water
out of the cold drain cock.

I wonder if it will be worth draining the whole system completely??

Any other ideas?????

Cheers

blister72




blister72 wrote:
Yep, I did that too - there was no air in the heating system
whatsoever.

blister72


Richard Polhill wrote:
"blister72" wrote in news:1122044859.947705.142380
@g49g2000cwa.googlegroups.com:

I then wondered if there is 'air' in the system or some leak? I've bled
all the radiators and thats was all ok. Checked the header tank and
plenty of water in there.


Have you bled the air from the system bleed valve too? usually it'll be
near the pump, valve, etc (in the airing cupboard) and will be a length of
copper pipe sticking up out of the system with a bleed valve on top. It'll
be higher than the pump, valve and coil.

Rich

--
Rich P
Replace .invalid with .com to reply.

In an earlier contribution to this discussion,
blister72 wrote:

I've done a bit more investigating this morning.....

The boiler fires up when I switch the heating and water on.
The cold entry pipe into the boiler is cold, as it should be.
The hot water pipe from the boiler is lukewarm.
The boiler itself is hot but not very hot as it usually is.

After about 5 minutes, the boiler then shuts down.

I am now wondering if there is an airlock in the boiler itself????

The cold entry pipe has a drain cock but there isn't one on the hot
pipe. I wouldn't be able to get rid of the airlock by draining water
out of the cold drain cock.

I wonder if it will be worth draining the whole system completely??

Any other ideas?????

Cheers

blister72

Is it a vented system with a small fill & expansion tank in the attic? (Not
to be confused with the large header tank for the domestic hot water).

If so, is there any water in it? It's not uncommon for the water to leak
and/or evaporate and for the ball valve to stick shut. This can deprive the
primary circuit of water - and may possibly explain your symptoms.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

It's a vented system and there is plenty of water in the header tank.
ball valve is ok.

In an earlier contribution to this discussion,
blister72 wrote:

It's a vented system and there is plenty of water in the header tank.
ball valve is ok.

You're definitely looking at the *small* tank, and not the big one, aren't
you?

In that case, is there a tap or gate valve in the pipe which feeds the
primary circuit from the bottom of this small tank? If so, could it
inadvertently have got turned off? It needs to be fully open.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Yes, I looked at the **small** tank - it is def. working ok, hasn't
been turned off. ballcock valve is working fine - releases water when I
push the ballcock valve down.

I have a **big** tank up in the loft which is the cold water store.

I will be draining the system today - nothing to lose by doing this. I
can then re-fill it and then balance all the rads again. If that
doesn't work, it's def. a problem with the boiler.




Set Square wrote:
In an earlier contribution to this discussion,
blister72 wrote:

It's a vented system and there is plenty of water in the header tank.
ball valve is ok.

You're definitely looking at the *small* tank, and not the big one, aren't
you?

In that case, is there a tap or gate valve in the pipe which feeds the
primary circuit from the bottom of this small tank? If so, could it
inadvertently have got turned off? It needs to be fully open.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.