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Default Central Heating - Boiler Firing, Radiators Cold

Hi - I'm looking for advice, please.

We have an oil fired boiler and recently I've noticed that our heating
doesn't seem to be working properly. Normally, the boiler will fire
when the heating comes on and it will go off when the house has reached
the required temp (around 20 degress as controlled by our room
thermostat) - usually within 30 - 45 minutes. The radiators normally
begin to feel warm within 10 mins of the boiler firing. What I'm
seeing at the moment is that (occasionally - maybe three or four times
a week) the heating will come on and the boiler will fire up as normal.
However, the radiators do not get hot. The boiler continues to fire
for as long as the heating is on, but the radaiators do not get warm.

Another occasional problem is that when the heating and water come on
at around the same time in the morning, the heating may work but the
water does not get hot. I assume this is probably related?

We had a plumber come out last week and he inspected the system. He
said the electronic valve is fine and he re-mounted the pump as he said
it had been fitted on an angle, which is incorrect. He also vented the
pump, having confirmed it's working okay. Although the system now
seems quieter, we're still having the intermittant problems mentioned
above.

I suspect we have an intermittant problem with the pump. As well as
being concerned that the system isn't working as it should, I imagine
that we're using far more oil than necessary as the boiler is
continuing to fire with little or no effect? Or am I misunderstanding
what is happening here?

Any advice gratefully received.

Thanks - Paul.

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Posted to uk.d-i-y
 
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Default Central Heating - Boiler Firing, Radiators Cold

Hi

We've had the same problem before.

One of the things to test first is to switch off your heating system
from the boiler control panel and then just turn on your hot water tap.
If after turning on the hot water tap you notice that the radiators
feel a bit warm this means that there is a problem with the divertor
valve. The work around was that we flushed the entire system including
leaking the water out of the boiler and filled it up again to a bare
minimum level and then after a few hours it worked.

Hope this helps.

Regards,
Arif


wrote:
Hi - I'm looking for advice, please.

We have an oil fired boiler and recently I've noticed that our heating
doesn't seem to be working properly. Normally, the boiler will fire
when the heating comes on and it will go off when the house has reached
the required temp (around 20 degress as controlled by our room
thermostat) - usually within 30 - 45 minutes. The radiators normally
begin to feel warm within 10 mins of the boiler firing. What I'm
seeing at the moment is that (occasionally - maybe three or four times
a week) the heating will come on and the boiler will fire up as normal.
However, the radiators do not get hot. The boiler continues to fire
for as long as the heating is on, but the radaiators do not get warm.

Another occasional problem is that when the heating and water come on
at around the same time in the morning, the heating may work but the
water does not get hot. I assume this is probably related?

We had a plumber come out last week and he inspected the system. He
said the electronic valve is fine and he re-mounted the pump as he said
it had been fitted on an angle, which is incorrect. He also vented the
pump, having confirmed it's working okay. Although the system now
seems quieter, we're still having the intermittant problems mentioned
above.

I suspect we have an intermittant problem with the pump. As well as
being concerned that the system isn't working as it should, I imagine
that we're using far more oil than necessary as the boiler is
continuing to fire with little or no effect? Or am I misunderstanding
what is happening here?

Any advice gratefully received.

Thanks - Paul.


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Posted to uk.d-i-y
 
Posts: n/a
Default Central Heating - Boiler Firing, Radiators Cold

You're correct Roger - it isn't a combi-boiler (thanks anyway for your
suggestion, Arif). Any other ideas, anyone?

Thanks again....

  #5   Report Post  
Posted to uk.d-i-y
Roger Mills \(aka Set Square\)
 
Posts: n/a
Default Central Heating - Boiler Firing, Radiators Cold

In an earlier contribution to this discussion,
wrote:

Hi - I'm looking for advice, please.

We have an oil fired boiler and recently I've noticed that our heating
doesn't seem to be working properly. Normally, the boiler will fire
when the heating comes on and it will go off when the house has
reached the required temp (around 20 degress as controlled by our room
thermostat) - usually within 30 - 45 minutes. The radiators normally
begin to feel warm within 10 mins of the boiler firing. What I'm
seeing at the moment is that (occasionally - maybe three or four times
a week) the heating will come on and the boiler will fire up as
normal. However, the radiators do not get hot. The boiler continues
to fire for as long as the heating is on, but the radaiators do not
get warm.

Another occasional problem is that when the heating and water come on
at around the same time in the morning, the heating may work but the
water does not get hot. I assume this is probably related?

We had a plumber come out last week and he inspected the system. He
said the electronic valve is fine and he re-mounted the pump as he
said it had been fitted on an angle, which is incorrect. He also
vented the pump, having confirmed it's working okay. Although the
system now seems quieter, we're still having the intermittant
problems mentioned above.

I suspect we have an intermittant problem with the pump. As well as
being concerned that the system isn't working as it should, I imagine
that we're using far more oil than necessary as the boiler is
continuing to fire with little or no effect? Or am I misunderstanding
what is happening here?

Any advice gratefully received.

Thanks - Paul.


We need to know a lot more about the way your system is controlled to be
able to make any sensible suggestions. Is it fully pumped, or gravity
(convection) HW and pumped CH? [Clue: how many water pipes are connected to
the boiler? What size are they, and where do they go?] How many motorised
valves are there, and what type? [If system is fully pumped, there will
likely be one 3-port valve or two 2-port valves]. Is there a thermostat
strapped to the HW cylinder? (not the one incorporated into an immersion
heater, if any).

As a general point, if the boiler comes on but the radiators don't get hot,
it means that no water is flowing through them. This could be for any number
of reasons, including:
* faulty room thermostat (which thinks that the heating doesn't need to be
on, so the boiler is running just for the benefit of the HW)
* faulty zone valve
* faulty pump
* air-lock or blockage

If the boiler is purely keeping itself warm but not heating the HW or
radiators, it will be wasting energy - but not using as much it would when
there was proper circulation.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.




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Posted to uk.d-i-y
 
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Default Central Heating - Boiler Firing, Radiators Cold

wrote:
Hi - I'm looking for advice, please.

We have an oil fired boiler and recently I've noticed that our heating
doesn't seem to be working properly. Normally, the boiler will fire
when the heating comes on and it will go off when the house has reached
the required temp (around 20 degress as controlled by our room
thermostat) - usually within 30 - 45 minutes. The radiators normally
begin to feel warm within 10 mins of the boiler firing. What I'm
seeing at the moment is that (occasionally - maybe three or four times
a week) the heating will come on and the boiler will fire up as normal.
However, the radiators do not get hot. The boiler continues to fire
for as long as the heating is on, but the radaiators do not get warm.

Another occasional problem is that when the heating and water come on
at around the same time in the morning, the heating may work but the
water does not get hot. I assume this is probably related?

We had a plumber come out last week and he inspected the system. He
said the electronic valve is fine and he re-mounted the pump as he said
it had been fitted on an angle, which is incorrect. He also vented the
pump, having confirmed it's working okay. Although the system now
seems quieter, we're still having the intermittant problems mentioned
above.

I suspect we have an intermittant problem with the pump. As well as
being concerned that the system isn't working as it should, I imagine
that we're using far more oil than necessary as the boiler is
continuing to fire with little or no effect? Or am I misunderstanding
what is happening here?

Any advice gratefully received.

Thanks - Paul.



The most likely problem is the 3 port valve, less likely is the
controller that controls it, or the wiring to it. Metering the
controller output or valve input will tell you which.

For peace of mind I'd check the boiler isnt boiling, as if it is there
would be a danger (plastic header tank boiling and collapse). Its
unlikely.


NT

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Posted to uk.d-i-y
 
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Default Central Heating - Boiler Firing, Radiators Cold

Thanks for your responses guys, and sorry for the delaying in
responding. I took the cowardly way out and called a plumber. I was
lucky enough to find a superb OFTEC engineer who I'd recommend to
anyone - let me know if you want his details.

So, here's the story of the fix....

As stated in my original post, he suspected the pump as the original
installer (whom I'll also supply details of if required - so that he
can be avoided) had installed it on an angle which I now believe can
cause premature wear. He'd also fitted a larger pump (15/60?) and set
it to speed three - far too much for our small-ish three bedroomed
house, apparently. So, as the re-mounting of the pump hadn't helped,
he replaced it. But, this had no effect, unfortunately.

Secondly, he went to the boiler and realised that even though the fan
was spinning (that's why I assumed the boiler was running), it was only
firing intermittently. In this situation, apparently, the boiler
should 'lock-out' but this wasn't happening. The suspect component was
the control box. He spent an hour or so looking at this and finally
opted to fit a replacement. Two issues were identified when fiiting
the new control box - 1 - the new box hadn't been supplied with a new
PCE (is this correct? Photo- something or other) so the old one had to
be refitted, and 2 - the old box had been wired incorrectly, preventing
lock-out and causing the solenoid to burn up quite badly. So, a
replacement solenoid, too. Still no joy - further testing identified
the PCE thing as the most likely culprit.

So, next day, armed with a new PCE, the boiler eventually fired
correctly each and every time. We now have heat!

The plumber has offered to remove the new pump and control box for no
cost as they weren't necessarily required. However, I'm not keen to
store potential problems for the future so I'm happy to pay for these
and for them to remain. I have to say, too, that the overall bill for
his labour was MUCH lower than expected. He spent 3 hours on the first
day investigating and another 1.5 hours on the second finishing the
job. He supplied all the parts to me at cost price to him, too.

Finally, two further issues - he found the original boiler
commissioning document in the owner's manal. It hadn't been completed
or signed. He's also noticed that the pipework leading from the boiler
is of a narrower gauge than required and both pipes had been fitted to
the same side of the boiler, which means we have no cross-flow. He
suspects that this is why the larger pump was fitted and set to maximum
speed to compensate.

Amazing, isn't it? He's coming back in a few weeks to commission the
boiler (it's been installed for 7 years...), fit the correct fire valve
outside of the garage where the boiler is located (the current one is
actually inside the boiler casing - not much use if there is a fire)
and complete the relevant paperwork. At this point we'll be on the way
to having a correct installation.

So, every cloud has a silver lining. We have a much improved, working
heating system now and an excellent contact for servicing work in the
future. My wallet is a bit lighter, but not as light as I feared it
was going to be!

Thanks again, all.

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