I've started using my heating after the summer and the radiators are
taking a long time to heat-up, eg about an hour to get to 52 deg. I
don’t have a baseline for comparison, but the boiler is probably 25
yrs old & small, so it’s never been quick.

It had a good service in Sept & was declared in good order. The
engineer said that he’d adjusted something (burners?). IIRC he said
he’d got it down to something like 5 (not sure what unit of
measurement). I haven’t noticed hot water taking longer to heat,
although it may be.

I drained & refilled the system a week or so later and, while it was
the first time I’ve done it, all seemed to be fine (must admit I
didn’t test exhaustively).

I’m wondering if the changes made during the service are the most
likely cause or if it’s to do with when I drained & refilled?

Are there any adjustments I can make myself, I’m thinking of things
like: just run the boiler for longer, increase the pump speed,
increase the boiler thermostat?

Michael

In an earlier contribution to this discussion,
Michael D wrote:

I've started using my heating after the summer and the radiators are
taking a long time to heat-up, eg about an hour to get to 52 deg. I
don’t have a baseline for comparison, but the boiler is probably 25
yrs old & small, so it’s never been quick.

It had a good service in Sept & was declared in good order. The
engineer said that he’d adjusted something (burners?). IIRC he said
he’d got it down to something like 5 (not sure what unit of
measurement). I haven’t noticed hot water taking longer to heat,
although it may be.

I drained & refilled the system a week or so later and, while it was
the first time I’ve done it, all seemed to be fine (must admit I
didn’t test exhaustively).

I’m wondering if the changes made during the service are the most
likely cause or if it’s to do with when I drained & refilled?

Are there any adjustments I can make myself, I’m thinking of things
like: just run the boiler for longer, increase the pump speed,
increase the boiler thermostat?

Michael

Watch what the boiler does while the radiators are heating up. If the boiler
is running continuously, it would suggest that it is inadequate for the job
(or has had it's pressure regulator set too low - restricting its capacity).
If the boiler is frequently cycling on its own thermostat, it indicates that
your system is not absorbing heat as quickly as the boiler is producing it -
probably due to an insufficient rate of water circulation. This could be due
to:
* pump speed too low (or knackered pump)
* room thermostat set too low
* radiator valves (manual or thermostatic) set too low
* air locks in the system, preventing proper circulation

The last of these may be the most likely in view of the fact that you
drained and refilled the system. Try turning the pump up, and turning off
all but one radiator to force a lot of water through it and purge the air.
Then turn that one off, and another one on until you've been right round the
system. Bleed the rads frequently during this exercise.
--
Cheers,
Roger
______
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monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On 21 Oct, 14:26, "Roger Mills" wrote:

Watch what the boiler does while the radiators are heating up. If the boiler
is running continuously, it would suggest that it is inadequate for the job
(or has had it's pressure regulator set too low - restricting its capacity).

If the boiler is frequently cycling on its own thermostat, it indicates that
your system is not absorbing heat as quickly as the boiler is producing it -
probably due to an insufficient rate of water circulation. This could be due
to:
* pump speed too low (or knackered pump)
* room thermostat set too low
* radiator valves (manual or thermostatic) set too low
* air locks in the system, preventing proper circulation

The last of these may be the most likely in view of the fact that you
drained and refilled the system. Try turning the pump up, and turning off
all but one radiator to force a lot of water through it and purge the air.
Then turn that one off, and another one on until you've been right round the
system. Bleed the rads frequently during this exercise.
--
Cheers,
Roger


Thanks - that's really useful stuff. I'm fairly sure it's running
continuously (I'll check). To be honest I think that the boiler could
be a bit underpowered for the house, as it's old & at least 1 new rad
has been installed since it was put in approx 25 yrs ago.

However nothing's changed in that respect since last winter and it
would have been roasting hot much more quickly.

Michael

On 21 Oct, 14:26, "Roger Mills" wrote:

Watch what the boiler does while the radiators areheatingup. If the boiler
is running continuously, it would suggest that it is inadequate for the job
(or has had it's pressure regulator set too low - restricting its capacity).


I've just checked (apols it's taken a while, I've been away) and the
boiler is running continually while heating-up. As noted above I
think the boiler is probably a bit underpowered generally, but that's
not the root of the current problem as nothing's changed in that
respect since last winter. when it was operating OK.

Some more info:
- The boiler thermostat is set to 3 (out of 5). It hasn't really
been increased, AFAIK
- I've just run it for an hour and the outward flow pipe got up to
53 deg C. I checked one of the rads & it to to 52.

I don't know if this suggests any of the particular causes outlined
above?

Michael

In an earlier contribution to this discussion,
Michael D wrote:



I've just checked (apols it's taken a while, I've been away) and the
boiler is running continually while heating-up. As noted above I
think the boiler is probably a bit underpowered generally, but that's
not the root of the current problem as nothing's changed in that
respect since last winter. when it was operating OK.


Except that, in your initial post, you said that the boiler had been
serviced in September and that the fitter had 'adjusted' it.

My guess is that he has turned down the gas pressure regulator, restricting
the flow of gas - and hence the rate of heat production. Ask him exactly
what he did and, if necessary, get him to crank it up again.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Roger Mills wrote:
In an earlier contribution to this discussion,
Michael D wrote:



I've just checked (apols it's taken a while, I've been away) and the
boiler is running continually while heating-up. As noted above I
think the boiler is probably a bit underpowered generally, but that's
not the root of the current problem as nothing's changed in that
respect since last winter. when it was operating OK.


Except that, in your initial post, you said that the boiler had been
serviced in September and that the fitter had 'adjusted' it.

My guess is that he has turned down the gas pressure regulator,
restricting the flow of gas - and hence the rate of heat production.
Ask him exactly what he did and, if necessary, get him to crank it up
again.

Hmmm... "IIRC he said he'd got it down to something like 5". If all it
needs is a bit of turning up again I hope he doesn't have the nerve to try
and charge you for adjusting it.

Tim

In an earlier contribution to this discussion,
Tim wrote:

Roger Mills wrote:
In an earlier contribution to this discussion,
Michael D wrote:



I've just checked (apols it's taken a while, I've been away) and the
boiler is running continually while heating-up. As noted above I
think the boiler is probably a bit underpowered generally, but
that's not the root of the current problem as nothing's changed in
that respect since last winter. when it was operating OK.


Except that, in your initial post, you said that the boiler had been
serviced in September and that the fitter had 'adjusted' it.

My guess is that he has turned down the gas pressure regulator,
restricting the flow of gas - and hence the rate of heat production.
Ask him exactly what he did and, if necessary, get him to crank it up
again.

Hmmm... "IIRC he said he'd got it down to something like 5". If all
it needs is a bit of turning up again I hope he doesn't have the
nerve to try and charge you for adjusting it.

Tim

Yes indeed - though he didn't say *what* he'd got down to 5! If this is
mbars of gas pressure, it's *very* low - and even if it's inches of water,
it's probably well below the maximum setting. Or could it be something
else - relating to a flue gas analyser reading, for instance?
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On Nov 2, 10:06*pm, Michael D wrote:
On 21 Oct, 14:26, "Roger Mills" wrote:

Watch what the boiler does while the radiators areheatingup. If the boiler
is running continuously, it would suggest that it is inadequate for the job
(or has had it's pressure regulator set too low - restricting its capacity).

I've just checked (apols it's taken a while, I've been away) and the
boiler is running continually while heating-up. *As noted above I
think the boiler is probably a bit underpowered generally, but that's
not the root of the current problem as nothing's changed in that
respect since last winter. when it was operating OK.

Some more info:
* - *The boiler thermostat is set to 3 (out of 5). It hasn't really
been increased, AFAIK
* - *I've just run it for an hour and the outward flow pipe got up to
53 deg C. *I checked one of the rads & it to to 52.

how long did boiler output take to reach 53C? Critical info


NT

On 4 Nov, 10:11, NT wrote:

how long did boiler output take to reach 53C? Critical info

NT


That was the temp after 1 hour (I suspect it would have got a bit
hotter if I'd kept measuring). I'd never timed it before, but at a
guess it used to take about 30 - 45 mins.

Unfortunately I don't know what measurement it was that was 5 (I was
hoping that there was a standard unit).

I've got the company coming back on Friday to have a look at it. We
agreed that if it's down to the burners then it's FOC, but if it's
something else then I'll have to pay. So I'm keen to make sure that
there isn't anything obvious ...

Michael

On Nov 4, 10:56*am, Michael D wrote:
On 4 Nov, 10:11, NT wrote:



how long did boiler output take to reach 53C? Critical info

NT

That was the temp after 1 hour (I suspect it would have got a bit
hotter if I'd kept measuring). *I'd never timed it before, but at a
guess it used to take about 30 - 45 mins.

If it took a whole hour to reach that, then surely your boiler is
putting out way too little power. This is not a case of an
underspecced boiler, sounds more like a grossly misadjusted one.


NT