All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years
ago, I had the system flushed at the recommendation of the boiler
installer (actually it turned out that the system didn't need
flushing ... grr). The water going to taps is very hot, but the water
going into the heating system is barely above body temperature feeling
the pipes coming away from the boiler. Does anyone have any
suggestions as to what might have happened?

Jon

On Dec 12, 1:04*pm, Jon Connell wrote:
All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years
ago, I had the system flushed at the recommendation of the boiler
installer (actually it turned out that the system didn't need
flushing ... grr). The water going to taps is very hot, but the water
going into the heating system is barely above body temperature feeling
the pipes coming away from the boiler. Does anyone have any
suggestions as to what might have happened?

Jon

Perhaps it's not pumping and they are getting warm simply by
convection.

wrote in message
...
On Dec 12, 1:04 pm, Jon Connell wrote:
All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years
ago, I had the system flushed at the recommendation of the boiler
installer (actually it turned out that the system didn't need
flushing ... grr). The water going to taps is very hot, but the water
going into the heating system is barely above body temperature feeling
the pipes coming away from the boiler. Does anyone have any
suggestions as to what might have happened?

Jon

Perhaps it's not pumping and they are getting warm simply by
convection.

Perhaps a motorised valve problem - jammed or worn and not fully diverting.

Jon Connell wrote:

All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years
ago, I had the system flushed at the recommendation of the boiler
installer (actually it turned out that the system didn't need
flushing ... grr). The water going to taps is very hot, but the water
going into the heating system is barely above body temperature feeling
the pipes coming away from the boiler. Does anyone have any
suggestions as to what might have happened?

Jon

Top of my checklist would be a failed zone valve motor. If it's a
system with 2-port valves you might find a little lever on the valve
body which manually opens the valve. If you do it should move very
very easily when the system is calling for heat (ie ON) and quite
slowly as you spin all the gears when the system is off. If it's
stiff in both cases the motor has failed which is not unusual (I keep
a spare in my DIY kit) and easy to fix. If that has happened you can
get heat in the short term by latching it open.

There are plenty of other possibilities but IME that's the Occam's
Razor solution.

In an earlier contribution to this discussion,
Jon Connell wrote:

All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years
ago, I had the system flushed at the recommendation of the boiler
installer (actually it turned out that the system didn't need
flushing ... grr). The water going to taps is very hot, but the water
going into the heating system is barely above body temperature feeling
the pipes coming away from the boiler. Does anyone have any
suggestions as to what might have happened?

Jon

Is it a combi boiler which produces 'instantaneous' hot water, or do you
have a hot water cylinder.

What reading is shown on the sealed system's pressure gauge?
--
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 12 Dec, 15:29, "Roger Mills" wrote:
Is it a combi boiler which produces 'instantaneous' hot water, or do you
have a hot water cylinder.

It's a combi.

What reading is shown on the sealed system's pressure gauge?

A little over 1 bar.

Jon

On 12 Dec, 14:41, Calvin wrote:
Top of my checklist would be a failed zone valve motor. *If it's a
system with 2-port valves you might find a little lever on the valve
body which manually opens the valve. *If you do it should move very
very easily when the system is calling for heat (ie ON) and quite
slowly as you spin all the gears when the system is off. *If it's
stiff in both cases the motor has failed which is not unusual (I keep
a spare in my DIY kit) and easy to fix. *If that has happened you can
get heat in the short term by latching it open.

Sounds plausible, thanks. I'll go take a look. And then get on the
phone to rant at the bloke who supposedly serviced the boiler (he
thought the heating problem was the TRVs on the rads sticking, which
sounds like nonsense as some are new and all rads have the same
problem and got it at the same time).

Jon

In an earlier contribution to this discussion,
Jon Connell wrote:

On 12 Dec, 15:29, "Roger Mills" wrote:
Is it a combi boiler which produces 'instantaneous' hot water, or do
you have a hot water cylinder.

It's a combi.

What reading is shown on the sealed system's pressure gauge?

A little over 1 bar.

Jon

In that case I'd tend to suspect either the pump or the diverter valve in
the boiler.
--
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 Fri, 12 Dec 2008 05:04:14 -0800, Jon Connell wrote:

All the radiators in my house have fairly suddenly developed a problem
with not getting hot (it's happened over the course of a week or so at
most). It's a sealed system and during some boiler trouble 2 years ago,
I had the system flushed at the recommendation of the boiler installer
(actually it turned out that the system didn't need flushing ... grr).
The water going to taps is very hot, but the water going into the
heating system is barely above body temperature feeling the pipes coming
away from the boiler. Does anyone have any suggestions as to what might
have happened?

Jon

Start with the simple stuff first, has someone inadvertently moved the
heating temperature setting on the boiler?


There are dozens of possibilities. Make and model will eliminate a number
of them.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On 12 Dec, 20:58, Ed Sirett wrote:
Start with the simple stuff first, has someone inadvertently moved the
heating *temperature setting on the boiler?

There are dozens of possibilities. Make and model will eliminate a number
of them.

It's a WB HighFlow 400 (an infamous combi if my googling is right).
I've given the diverter valve a bash tonight and it's not helped it
unjam and I can't see any obvious way on this boiler to force it to
open the CH flow. One I did notice is that the temperature of the the
rads is not constant: some are warmer than others and a couple and
cold at the bottom and warmish at the top.

Jon

On Fri, 12 Dec 2008 13:57:16 -0800, Jon Connell wrote:

On 12 Dec, 20:58, Ed Sirett wrote:
Start with the simple stuff first, has someone inadvertently moved the
heating Â*temperature setting on the boiler?

There are dozens of possibilities. Make and model will eliminate a
number of them.

It's a WB HighFlow 400 (an infamous combi if my googling is right). I've
given the diverter valve a bash tonight and it's not helped it unjam and
I can't see any obvious way on this boiler to force it to open the CH
flow. One I did notice is that the temperature of the the rads is not
constant: some are warmer than others and a couple and cold at the
bottom and warmish at the top.

Jon

WB offer a fixed price repair. Since this is likely to be above the
average amount of work to put right it is probably a very good deal.




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

In message
, Jon
Connell writes
On 12 Dec, 20:58, Ed Sirett wrote:
Start with the simple stuff first, has someone inadvertently moved the
heating *temperature setting on the boiler?

There are dozens of possibilities. Make and model will eliminate a number
of them.

It's a WB HighFlow 400 (an infamous combi if my googling is right).

I think that everyone who googles for their particular boiler thinks
that their boiler is the worst around

with the exception of the owners of Potterton Suprimas who know that
they are

The Highflow is not even premier division


--
geoff

On Sat, 13 Dec 2008 21:54:02 +0000, geoff wrote:

In message
, Jon
Connell writes
On 12 Dec, 20:58, Ed Sirett wrote:
Start with the simple stuff first, has someone inadvertently moved the
heating Â*temperature setting on the boiler?

There are dozens of possibilities. Make and model will eliminate a
number of them.

It's a WB HighFlow 400 (an infamous combi if my googling is right).

I think that everyone who googles for their particular boiler thinks
that their boiler is the worst around

with the exception of the owners of Potterton Suprimas who know that
they are

The Highflow is not even premier division

I agree, however when things need fixing they are very more difficult to
work on than smaller boilers, IMHO.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On 12 Dec 2008, 20:58, Ed Sirett wrote:
Start with the simple stuff first, has someone inadvertently moved the
heating *temperature setting on the boiler?

There are dozens of possibilities. Make and model will eliminate a number
of them.

No problems with the diverter valve or the pump. It turns out that the
temperature dial for the heating system is working backwards: turning
it towards hot actually causes the boiler to stop heating earlier and
it's the "cold" setting that results it in it heating fully. I think
we must have nudged it around towards hot (now cold) at some point and
then gradually turned it colder and colder as we tried to heat up the
rads. A couple of years ago, it was replaced by Worcester Bosch, so my
guess is that they screwed it in upside down. Time to get on the phone
and get some money back, I think.

Jon