Folks

Summary - Switching on central heating doesn't start gas boiler, hot
water needs to be switched on as well - electrician claims this is the
normal way these things are configured. Is he talking through his..?

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I'm just getting to the end of a bit of a renovation and while I was
doing it I had my hot water system replaced with a pressurised system.

The existing natural gas boiler was retained and the central heating
hasn't been pressurised.

The electrician onsite fitted a new control system but when I went to
test the system (he'd already left) I discovered that putting the
central heating on switched on the central heating pump but didn't
fire up the boiler. Switching on the hot water fires up both the
boiler and the hot water pump.

I called the electrician and explained the situation and he tells me
that this is the way it's supposed to be, if you want the central
heating on you have to set the hot water to come on at the same time.

This certainly wasn't the case with the old system and I think he's
having me on but he's so adamant about it that he's got me doubting
myself. He says he can set it up the way I want i.e. either can be on
independently but it will be really complex and require a relay, etc
and then started to try to baffle me with electrical terms (I hadn't
the heart to tell him I have a degree in Electrical and Electronic
Engineering - I wouldn't make any claims to be an electrician but I
know enough to know it sounded like crap)

Could anyone offer an unbiased opinion? I don't want to start a fight
with what have otherwise been a great team of builders.

thanks

tommy

In article ,
Tommy Gilchrist wrote:
The existing natural gas boiler was retained and the central heating
hasn't been pressurised.

The electrician onsite fitted a new control system but when I went to
test the system (he'd already left) I discovered that putting the
central heating on switched on the central heating pump but didn't
fire up the boiler. Switching on the hot water fires up both the
boiler and the hot water pump.

I called the electrician and explained the situation and he tells me
that this is the way it's supposed to be, if you want the central
heating on you have to set the hot water to come on at the same time.

This certainly wasn't the case with the old system and I think he's
having me on but he's so adamant about it that he's got me doubting
myself. He says he can set it up the way I want i.e. either can be on
independently but it will be really complex and require a relay, etc
and then started to try to baffle me with electrical terms (I hadn't
the heart to tell him I have a degree in Electrical and Electronic
Engineering - I wouldn't make any claims to be an electrician but I
know enough to know it sounded like crap)

Could anyone offer an unbiased opinion? I don't want to start a fight
with what have otherwise been a great team of builders.

He's talking bollox. ;-)

Do you know what wiring plan has been used? Have you a three port valve,
or motorised valves, or none at all?

However, on the most basic system which relies on gravity circulation for
hot water heating the hot water will work on its own while the central
heating only comes on when the pump runs. If a fully pumped system - which
it sounds like you have you if the pump runs for the hot water - it's a
wiring etc fault if you can't have heating without hot water. You can have
either or both with this system.

I'd guess there is a link missing in the programmer, if it's Y plan (three
port valve which is perhaps the most common)

Have a look at this site which shows that link or do a Google for lots of
others.

http://www.gas-news.co.uk/feature12.htm

This newsgroup's FAQ gives the common wiring diagrams too.

--
*No husband has ever been shot while doing the dishes *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 09 Jul 2006 12:46:07 +0100, "Dave Plowman (News)"
wrote:


He's talking bollox. ;-)

Do you know what wiring plan has been used? Have you a three port valve,
or motorised valves, or none at all?

There is a single pump and a single motorised valve. The pump sends
the output of the boiler to both the unvented cylinder and the
radiators but the motorised valve sits between the output and the
radiators.

Have a look at this site which shows that link or do a Google for lots of
others.

http://www.gas-news.co.uk/feature12.htm

Thanks for the link. I'll have a look at the wiring later in the week
(Kitchen fitting for the next day or so)


This newsgroup's FAQ gives the common wiring diagrams too.

On Sun, 09 Jul 2006 11:29:05 +0100 someone who may be Tommy
Gilchrist wrote this:-

The electrician onsite fitted a new control system but when I went to
test the system (he'd already left) I discovered that putting the
central heating on switched on the central heating pump but didn't
fire up the boiler. Switching on the hot water fires up both the
boiler and the hot water pump.

I called the electrician and explained the situation and he tells me
that this is the way it's supposed to be,

No quite.

In Ye Olden Days heating systems were wired up so that the "hot
water" control activated the boiler. Water would circulate to the
cylinder by gravity. The "central heating" control activated the
pump for the heating, via a thermostat. Simple, but not ideal.

When you "had my hot water system replaced with a pressurised
system" what work did they do? I assume that they fitted a thermal
store in place of the cylinder, or did they fit a multipoint heater?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

I called the electrician and explained the situation and he tells me
that this is the way it's supposed to be, if you want the central
heating on you have to set the hot water to come on at the same time.

It is now a legal requirement that the heating and hot water controls are
independent. The system as installed does not comply with Part L of the
building regulations.

Christian.