CH/HW system is a Y-Plan design, Baxi Solo 40PF boiler.

Yesterday there was a hell of a racket coming from the boiler - a series
of bangs maybe a second apart, a bit of wheezing etc., there's also
sounds of bubbling through other parts of the pipe system. I'm not sure,
but the boiler may cut out for a few minutes (I'm not sure of its
characteristics before this started - I would have thought it'd be on
continuous whilst there was a demand for heating the HW cylinder?)

My thoughts are that with the temperature dropping recently, the CH has
kicked in, and disturbed the last 8 months of static water in the
radiators, kicking up sediment, and presumably kicking this into the
boiler clogging it up (heat exchanger?).

So, does the above make sense?, is this a likely scenario?

My thoughts to remedy this, bearing in mind the boiler is enclosed in a
kitchen unit and the access to the pipework is, at best, minimal, is to
drain the CH system down (via lowest radiator), probably leave the
cold-feed on (F&E tank in loft) to do sort-of a low-pressure flush of
the system.

I might also be tempted to fit one of those magnetic sludge removal
devices (e.g. Fernox boiler buddy) to try to remove the suspended matter
from the system

Does the above solution sound practical?, or is it (metaphorically
speaking) ****ing in the wind? If so, barring reaching for the yellow
pages and my flexible friend, is there anything else I should be trying?

Regards

Mike

On 2006-11-02 06:49:50 +0000, Mike Dodd said:

CH/HW system is a Y-Plan design, Baxi Solo 40PF boiler.

Yesterday there was a hell of a racket coming from the boiler - a
series of bangs maybe a second apart, a bit of wheezing etc., there's
also sounds of bubbling through other parts of the pipe system. I'm not
sure, but the boiler may cut out for a few minutes (I'm not sure of its
characteristics before this started - I would have thought it'd be on
continuous whilst there was a demand for heating the HW cylinder?)

My thoughts are that with the temperature dropping recently, the CH has
kicked in, and disturbed the last 8 months of static water in the
radiators, kicking up sediment, and presumably kicking this into the
boiler clogging it up (heat exchanger?).

So, does the above make sense?, is this a likely scenario?

It's possible. Have you tried bleeding the radiators?


My thoughts to remedy this, bearing in mind the boiler is enclosed in a
kitchen unit and the access to the pipework is, at best, minimal, is to
drain the CH system down (via lowest radiator), probably leave the
cold-feed on (F&E tank in loft) to do sort-of a low-pressure flush of
the system.

That would be one way but have very limited results. If the system is
full of sludge, telltale signs are if there is a gas released from the
radiators when opening the vents and it can be lit. This is hydrogen
from corrosion. Another is if the centre areas of the radiators at
the bottom feel cool when the system is hot.

A better method of cleaning is to flush at each radiator position.
Leave the water supply to the header tanks or filling loop on.
Use Plastic sheet and old towels and newspaper on the floor. Close
the radiator valves noting the lockshield position. Position vessels
to collect the water. Cat trays are good for this. Bear in mind that
water from a sludged heating system and the sludge are indellible dyes.
Undo the union nuts on the valve slowly and allow the radiator
water to drain into the vessels. Tip to let remainder out. Fit small
plastic bags to the valve tails with rubber bands and take the radiator
outside. Flush through with mains hose or pressure washer.
At the radiator position, open each valve in turn to flush water from
the pipes together with crud.
Refit the radiator.

This procedure should be started upstairs on each radiator and then
downstairs. Finally flush at the boiler if you can.

After this add a flushing agent to the system, refill and run it for
the recommended time - usually a week. The hot water helps to dissolve
other material. It is not a substitute for flushing properly.

Finally flush through with plain water and add corrosion inhibitor.

While doing this exercise, check that there is neither pumping over or
sucking down of air if you have a header tank. If there is, post
again for comments on that. The problem is that these introduce
oxygen into the system and promote corrosion.

An alternative approach is to rent a power flushing machine from a hire
place. These are generally attached at the pump and water forced
round opening one radiator at a time.


Another is to pay a heating engineer to do this. Expect to pay several
hundred for this.

Finally you could ask BG to do it. They will subcontract to a local
engineer and mark up the deal. A second mortgage for this one.




I might also be tempted to fit one of those magnetic sludge removal
devices (e.g. Fernox boiler buddy) to try to remove the suspended
matter from the system

This is the wrong approach. These things are like sticking a band aid
on a major wound. You can remove some sludge from the system. In the
meantime, the radiators will continue to corrode and eventually
expensively fail. It is much better to prevent corrosion in the first
place and it is very easy and much cheaper to do that.



Does the above solution sound practical?, or is it (metaphorically
speaking) ****ing in the wind? If so, barring reaching for the yellow
pages and my flexible friend, is there anything else I should be trying?

Regards

Mike

Andy Hall wrote:

My thoughts are that with the temperature dropping recently, the CH
has kicked in, and disturbed the last 8 months of static water in the
radiators, kicking up sediment, and presumably kicking this into the
boiler clogging it up (heat exchanger?).

So, does the above make sense?, is this a likely scenario?

It's possible. Have you tried bleeding the radiators?


Yes - no gas from any (immediate spurt of water)



My thoughts to remedy this, bearing in mind the boiler is enclosed in
a kitchen unit and the access to the pipework is, at best, minimal, is
to drain the CH system down (via lowest radiator), probably leave the
cold-feed on (F&E tank in loft) to do sort-of a low-pressure flush of
the system.

That would be one way but have very limited results. If the system is
full of sludge, telltale signs are if there is a gas released from the
radiators when opening the vents and it can be lit. This is hydrogen
from corrosion. Another is if the centre areas of the radiators at
the bottom feel cool when the system is hot.

Actually, can't get any heat to the rads (sorry, the story is developing
from 6am this morning when I was getting ready for work)

An alternative approach is to rent a power flushing machine from a hire
place. These are generally attached at the pump and water forced
round opening one radiator at a time.

Hmmm, that's an idea.



Another is to pay a heating engineer to do this. Expect to pay several
hundred for this.


That's a less attractive idea.


Finally you could ask BG to do it. They will subcontract to a local
engineer and mark up the deal. A second mortgage for this one.


Hmmm.




I might also be tempted to fit one of those magnetic sludge removal
devices (e.g. Fernox boiler buddy) to try to remove the suspended
matter from the system

This is the wrong approach. These things are like sticking a band aid
on a major wound. You can remove some sludge from the system. In the
meantime, the radiators will continue to corrode and eventually
expensively fail. It is much better to prevent corrosion in the first
place and it is very easy and much cheaper to do that.


My plan was to use this to mop up the sludge that'd remain in the system
- although I agree this would be better done via a proper flush.

In an earlier contribution to this discussion,
Mike Dodd wrote:

CH/HW system is a Y-Plan design, Baxi Solo 40PF boiler.

Yesterday there was a hell of a racket coming from the boiler - a
series of bangs maybe a second apart, a bit of wheezing etc., there's
also sounds of bubbling through other parts of the pipe system. I'm
not sure, but the boiler may cut out for a few minutes (I'm not sure
of its characteristics before this started - I would have thought
it'd be on continuous whilst there was a demand for heating the HW
cylinder?)
My thoughts are that with the temperature dropping recently, the CH
has kicked in, and disturbed the last 8 months of static water in the
radiators, kicking up sediment, and presumably kicking this into the
boiler clogging it up (heat exchanger?).

So, does the above make sense?, is this a likely scenario?

My thoughts to remedy this, bearing in mind the boiler is enclosed in
a kitchen unit and the access to the pipework is, at best, minimal,
is to drain the CH system down (via lowest radiator), probably leave
the cold-feed on (F&E tank in loft) to do sort-of a low-pressure
flush of the system.

I might also be tempted to fit one of those magnetic sludge removal
devices (e.g. Fernox boiler buddy) to try to remove the suspended
matter from the system

Does the above solution sound practical?, or is it (metaphorically
speaking) ****ing in the wind? If so, barring reaching for the yellow
pages and my flexible friend, is there anything else I should be
trying?
Regards

Mike

It's not clear from your post whether or not the system is actually
working - or whether it runs for a very short time, accompanied by the
banging, and then stops?

If it's *not* running, it sounds to me as if the pump has failed. If the
pump isn't working, the water in the boiler will boil - sending lots of
steam into the pipework - which may account for the noise.

If it *is* working, it could just be that there's air in the radiators,
which is getting circulated now that the heating has come on. Have you
checked that there is water in the F&E tank? This could have dried up if the
ball-valve is stuck shut - causing air to be drawn into the system.

So make sure the ball valve is working, and then bleed all the radiators and
see whether that makes any difference.
--
Cheers,
Roger
______
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Roger Mills wrote:

It's not clear from your post whether or not the system is actually
working - or whether it runs for a very short time, accompanied by the
banging, and then stops?

If it's *not* running, it sounds to me as if the pump has failed. If the
pump isn't working, the water in the boiler will boil - sending lots of
steam into the pipework - which may account for the noise.


It seems to run for a short time, with banging, then stops. After it
stops there's continued rumbling and moaning in the pipework, which
supports your boiling idea.

Pump failed?, hmmm, a fairly new pump, and it *sounds* like it's
turning, and it vibrates like it's turning... any chance the impellor
could have fallen off?

(also speed control does have the appropriate effect on the sound)


If it *is* working, it could just be that there's air in the radiators,
which is getting circulated now that the heating has come on. Have you
checked that there is water in the F&E tank? This could have dried up if the
ball-valve is stuck shut - causing air to be drawn into the system.

So make sure the ball valve is working, and then bleed all the radiators and
see whether that makes any difference.


Water in F&E - albiet luke warm, well, bearly tepid, tbh(hmmm, why?),
and very, very sludgy (ok, water level maybe 3 inches, and hand dipped
in - sludge feels 5-10mm deep on the base of the tank).

Radiators - bleed them all - no air/gas - just water.

Mike Dodd wrote:

If it's *not* running, it sounds to me as if the pump has failed. If
the pump isn't working, the water in the boiler will boil - sending
lots of steam into the pipework - which may account for the noise.


It seems to run for a short time, with banging, then stops. After it
stops there's continued rumbling and moaning in the pipework, which
supports your boiling idea.

Pump failed?, hmmm, a fairly new pump, and it *sounds* like it's
turning, and it vibrates like it's turning... any chance the impellor
could have fallen off?

(also speed control does have the appropriate effect on the sound)


Stupid question time - any way to test the pump, or do I have to drain
the system (looking like I'm gonna have to do this anyway), remove and
place carefully in a bucket of water?

Mike Dodd wrote:
Mike Dodd wrote:

If it's *not* running, it sounds to me as if the pump has failed. If
the pump isn't working, the water in the boiler will boil - sending
lots of steam into the pipework - which may account for the noise.


It seems to run for a short time, with banging, then stops. After it
stops there's continued rumbling and moaning in the pipework, which
supports your boiling idea.

Pump failed?, hmmm, a fairly new pump, and it *sounds* like it's
turning, and it vibrates like it's turning... any chance the impellor
could have fallen off?

(also speed control does have the appropriate effect on the sound)


Stupid question time - any way to test the pump, or do I have to drain
the system (looking like I'm gonna have to do this anyway), remove and
place carefully in a bucket of water?

Actually, I could believe that it is the pump...

The boiler, from cold, will burn for quite some time - couple of
minutes. Bangs, stops, waits a while, tries again - burns for a few
seconds (overheating?)

Then, upstairs, having turned off the HW and CH demand the pipework
under the pump (boiler side) is distinctly warmer from the output from
the pump - which I think is being heated by conduction, only.

So...

Tomorrow, drain, remove pump, quick test and off to a plumbers centre
for a replacement, if necessary.

Thanks for help, will report back.

In an earlier contribution to this discussion,
Mike Dodd wrote:


Stupid question time - any way to test the pump, or do I have to
drain the system (looking like I'm gonna have to do this anyway),
remove and place carefully in a bucket of water?

Most pumps have a removeable end cap (on the end of the motor, furthest from
the water connections). If you remove that, you can see whether the shaft is
rotating. If it isn't, it may be jammed by a bit of crud. there should be a
screwdriver slot in the end of the shaft, enabling you to rotate it. You may
be able to free it if it *is* jammed.

If the shaft *is* rotating, it's still possible (as you suggested earlier)
that the impellor has become detached fom the shaft. You can't check that
without removing the pump.

Actually, I could believe that it is the pump...

The boiler, from cold, will burn for quite some time - couple of
minutes. Bangs, stops, waits a while, tries again - burns for a few
seconds (overheating?)

Then, upstairs, having turned off the HW and CH demand the pipework
under the pump (boiler side) is distinctly warmer from the output from
the pump - which I think is being heated by conduction, only.

So...

Tomorrow, drain, remove pump, quick test and off to a plumbers centre
for a replacement, if necessary.

Thanks for help, will report back.

Does your pump have service valves or gate valves either side? If so -
provided they work(!) - you can turn them off and remove the pump without
needing to drain the system. Fit new rubber washers when you put it back
together. [If you have to replace the pump, it should come with new washers
anyway].
--
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!