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Heating Questions and Answers

A digest of questions and answers about boiler installation and heating problems from my 2004 forum.
There is no support for your heating problems from me via e-mail or phone. Please contact a local plumber or visit the new forum.

Noisey boiler Boiler clearance Sealed system water pressure low Immersion heater corroded Pump running constantly Draining system One pipe system Gas fire flue noise
Noisey boiler

I had a new boiler professionally fitted a couple of years ago. Periodically it makes hissing and banging noises (kettling I believe) when starting a heating or hot water session. This lasts for a few minutes after which the boiler cuts out.

I’ve mentioned this to the maintenance company and they suggested at first that the system needed bleeding but I’ve done that and I still have the problem.

The boiler is a Potterton Suprima fitted on an external wall in the first floor bathroom airing cupboard just above the hot water cylinder.

Any insight into the problem would be welcome. Thanks, Dave

Was the boiler fitted to an existing system and if so was it flushed before installation of the new boiler? DAVID

Yes, it was fitted to an existing system and I'm pretty sure it was flushed out. The new boiler is in a different position to the old one - about eight feet higher. Dave

I'm afraid it may need flushing again if you want to stop the kettling. You could try a proprietary additive to stop the noise but in my experience they are not that effective. The fact that the boiler is higher now should not be an issue unless air is getting into the system and the cause of sludging. DAVID

I need to change a radiator so I can flush the system then. Is there a special way of doing this or do I just let water run through. Do I need a flushing agent? Dave

Power flushing will do the best job enquire at your local tool hire shop for the equipment needed. Failing this, two to three days before you change the radiator add a cleanser to the system i.e. Fernox Superfloc and allow to circulate. When you change the radiator drain the system completely and flush thoroughly with water. Refill and add inhibitor.

Many thanks David for your valuable advice.

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Boiler clearance

Question:-

Does anyone know what access to my boiler I need to provide. The boiler is currently in a corner and faces the way I want my new kitchen cabinets to go. Do I need to provide easy front access (ie open a cupboard door and the front panel is facing) or whether I can provide side access through a cupboard (ie open a cupoard door and the front of the bolier is accessed through the side of the cupboard)
Many thanks

Reply:-

You must comply with the clearances given in the installation instructions, they vary between boilers. You must also consider ventilation requirements if you intend to close the boiler in, this should also be in the installation instructions but if you don't have these speak to the manufacturer and ask them to send you some.

DAVID

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Sealed system water pressure low

Question:-

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Immersion heater corroded

Question:-

My breaker on my fuse box ,for my water heater, kept tripping out. I assume this means that I have an electrical fault somewhere, or that the load is too large on some part of the circuit. I flicked the switch back, and this was all fine. However, it did it again, and when I flicked it back it blue sparked at me. This, i guessed, was the fuse blowing, as it should. I now have no hot water at all (except for my shower), and the immersion tank is cold (Economy 7). I haver replaced the circuit breaker, but still no joy. I'm guessing it could be the thermostat that has blown, but thought I'd ask some people who know what they are talking about.
There may not be enough info here for an educated guess, so if you need more, I'm happy to try anything.
Thanks in advance!

Smithsi's Reply:-
I have experienced the same problem. The problem is due to the element in the hot water tank, corroding due to hard water, this causes a short, which is what is tripping the fuse box. Mine has just gone after 18 months. Solution is to drain the tank and take out the element and replace with a new element (you should see it corroded through). I'm no plumber, but found this through experience

I'm sure Smithsi's reply is correct and you will have to replace the immersion heater but for longer life use an alloy element such as an Incoloy, Superloy type, instead of a copper one. Go to a plumber’s merchant or electrical wholesaler for one and not a diy shed.

DAVID

Nitros Reply:-
Agreed with david,you will find the diy type will only last about 12 months,and be about 12 quid,from a plumbing merchants will be about 22 quid and last about 24 months,so saves time and money doing it less but costs more in the first place.This being as said before in a hard water area

Thanks alot for all your help and friendly advice! Think I'll get myself down to a proper merchants and see what I can get. The parts seem cheaper than I was expecting, so am happy!
Thanks again!!!!

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Pump running constantly

Question:-

Hello.
My pump has been running constantly for the last couple of weeks. The heating hasn't been on for several weeks. Any ideas what the problem could be?
Thank you.

Hi
It depends on the system i.e. gravity HW pumped CH or fully pumped. If its a gravity HW pumped CH system then look at the programmer because it must be applying power to the pump when in the off position, if there is a room stat fitted see if this will stop the pump.
If you've a fully pumped system it’s more complicated but again check the programmer and test the room stat. If there is a diverter valve fitted check to see if it is operating properly.
If it's nothing fairly obvious you may be safer calling in a qualified electrician.

DAVID

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Draining system

Question:-

I've never worked on a system with a combi boiler before. I need to move an upstairs radiator at my daughters new house. Q1 - Do I have to drain the system down(if so, how?)or, as the pub know-all has told me, will the water hold itself back in the pipes? Q2 - How do I re-pressurise it?

Roger

Before you start you will have to locate the filling loop, this is often on pipe work near the boiler but may be an integral part of the boiler check the installation instructions. You will need to know how to use it too. Mains pressure water passes into the heating system via this loop and it should be disconnected when not in use. Make a note of the system pressure and refill to this level usually around 1bar.

To drain the system

It is possible to work on a sealed system with out draining but unless you’re sure of what you’re doing I would advise against it.

DAVID

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One pipe system

Question:-

I have a single pipe central heating system. It works fine and all the rads heat up properly. I need to change the boiler and add another rad and I'm not sure if I should convert to 2 pipe. People keep telling me it would be a lot more efficient but would it repay the cost and upheaval?
Would appreciate your view.
Cheers Steve

Hi Steve
One pipe systems where installed until the early seventies and they where really a left over from the even earlier unpumped gravity systems which were often found in larger houses.
Today no one would install a one pipe system. As for the efficiency, if you already have a one pipe system installed in your house I can't see that there would be any great improvement in removing it and installing a two pipe system. If it could be calculated, I think that the pay back time would be very long indeed.
Having said all that it is much easier to add extra radiators to a two pipe system, also if you decide to stick with the one pipe and install the new boiler the old system will need comprehensively cleansing.

DAVID

Good luck

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Noisey gas fire flue

DAVID

Question:-

I have a Baxi gas fireplace in my living room which works fine but because the ventilation flue connects directly into the back of the fireplace there is a great deal of noise when it's windy (and it can be very windy here in Scotland, like now!). The flue system exits the roof in a 5" or 6" duct topped with a ventilated cap with louvres all round.

I wondered if there is a device available that could be fitted to cut down the noise without restricting ventilation.

Any suggestions would be very much appreciated.

Bill [:(]

Different cowls can be fitted to the terminal and maybe a different one would reduce the wind noise but they must be suitable for gas and should be installed by a CORGI installer. It may not be possible to change a ridge terminal if that’s what you have. Do you know the manufacturer of the duct as they will be able to offer advice, Selkirk is a well known manufacturer for example. Another option that you may not want to consider is changing the fire as some types seem to be worse than others, inset living flue effect to my mind are worse than radiant types.

DAVID

David,

I'm not sure who the duct manufacturer is and it's a radiant type fire. The duct exits some way down the roof from the ridge. Originally the exit was to a ridge vent (this was virtually noiseless) but the installer advised that this was not appropriate for the new fire. I would be happy to have a Corgi installer try a different cowl but there seems not to be much information about on what's available. Anyway, thanks for your advice, much appreciated.

Bill [:I]

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