I want to know how combi boiler clocks/timers work...
 

Mine recently stopped working, that is to say it works for a bit, then
stops, then works for a bit.

"Works for a bit" means that the clock is audibly ticking, and the
mechanical clock rotates. "Stops" means neither of these things happen.

To my untrained eye it seems the power is running dry on the clock. The
strange thing to me is that I thought boilers were plugged into the
mains, so how could it run out of power?

Now an admission: I made a post on this yesterday, but I think it was
over specific in terms of detailing the manufacturer (Sime) etc. What
I'm looking for now is just some general guidance on how these things
work, as I'll probably get someone out to do it, and I don't want to get
stung. I just spoke to a guy who was very vague, talking about some
piece of kit between the power and the clock, which could go wrong.

Thanks, Dan

Now an admission: I made a post on this yesterday, but I think it was
over specific in terms of detailing the manufacturer (Sime) etc. What
I'm looking for now is just some general guidance on how these things
work, as I'll probably get someone out to do it, and I don't want to get
stung. I just spoke to a guy who was very vague, talking about some
piece of kit between the power and the clock, which could go wrong.

Set the timer to be on 24 hours a day. Replace your room thermostat with a
programmable type. Then it doesn't matter that your clock is knackered, and
you have the heating controls in the lounge, where they belong and all the
advantages of a programmable thermostat, such as selecting a specific
temperatures for different times of day.

This presumes that the same fault doesn't prevent the 24h option from
working.

Christian.

Christian McArdle wrote:
Set the timer to be on 24 hours a day. Replace your room thermostat with a
programmable type. Then it doesn't matter that your clock is knackered, and
you have the heating controls in the lounge, where they belong and all the
advantages of a programmable thermostat, such as selecting a specific
temperatures for different times of day.

This presumes that the same fault doesn't prevent the 24h option from
working.

Do you mean a wall hung thermostat? The only thermostat I have is one on
one of my rads (in my lounge). I don't think I have some master
thermostat. There is a control on the boiler which seems to make the
boiler turn on more often, but none that stops it turning on at all.

It works fine when it's manually switched on.

Thanks a lot,
Dan

Do you mean a wall hung thermostat? The only thermostat I have is one on
one of my rads (in my lounge). I don't think I have some master
thermostat.

Well, spend your money having one installed, rather than fixing the clock.
It will not only make the timing work, but will save you a fortune in gas,
as currently the boiler will be on for the entire time that heating is
selected on, not just when the house is cold. As it appears you don't even
have widespread TRVs, the house will likely overheat, too, causing really
quite appalling energy efficiency.

Christian.

Christian McArdle wrote:

Do you mean a wall hung thermostat? The only thermostat I have is one on
one of my rads (in my lounge). I don't think I have some master
thermostat.


Well, spend your money having one installed, rather than fixing the clock.
It will not only make the timing work, but will save you a fortune in gas,
as currently the boiler will be on for the entire time that heating is
selected on, not just when the house is cold. As it appears you don't even
have widespread TRVs, the house will likely overheat, too, causing really
quite appalling energy efficiency.

Thanks very much! I'll certainly have a look into this.

Dan

I don't think I have some master thermostat.

Well, spend your money having one installed, rather than fixing the clock.

P.S. Also, put TRVs on all your radiators, too, except for the room you
choose for your room thermostat. I prefer the lounge for this, as you get
tightest temperature control in the room selected. Some choose the hallway,
as it is often the coldest and most underheated room, so the heating stays
on until all rooms are hot. However, you mustn't choose a room with
alternative heating (such as a fireplace or gas fire) that is used
frequently, as it will fool the heating into shutting off, making the rest
of the house cold.

Doing all the above will not only save you (and the earth) a bomb, but will
actually improve the comfort of your home.

Christian.

Christian McArdle wrote:
Set the timer to be on 24 hours a day. Replace your room thermostat with a
programmable type. Then it doesn't matter that your clock is knackered, and
you have the heating controls in the lounge, where they belong and all the
advantages of a programmable thermostat, such as selecting a specific
temperatures for different times of day.

Silly question now perhaps, but do all boilers support these things?
I've started an email enquiry with Honeywell about their products, but
I'm not sure whether my boiler will allow a programmable thermostat to
be fitted. One would hope the interface to the boiler is a generic one
through standard inputs.

The boiler is no more than ten years old, I think.

Dan

Silly question now perhaps, but do all boilers support these things?
I've started an email enquiry with Honeywell about their products, but
I'm not sure whether my boiler will allow a programmable thermostat to
be fitted.

Every gas boiler ever made that uses electricity can support a programmable
thermostat. They will have one of three methods:

1. "Voltage free" contacts (just connect the thermostat terminals across the
boiler thermostat terminals)
2. "Call for heat" input (just connect the thermostat terminals across the
call for heat input and the live.
3. Main power input (just connect the thermostat terminals between live and
the boiler power input.

(3) Would be required for really ancient type boilers that just fire up when
there is electrical power. Think old cast iron lumps.

Most modern boilers use method (2), as it allows most flexibility in wiring,
although some (particularly combis) use method (1).

Christian.

Christian McArdle wrote:

Every gas boiler ever made that uses electricity can support a programmable
thermostat. They will have one of three methods:

1. "Voltage free" contacts (just connect the thermostat terminals across the
boiler thermostat terminals)
2. "Call for heat" input (just connect the thermostat terminals across the
call for heat input and the live.
3. Main power input (just connect the thermostat terminals between live and
the boiler power input.

(3) Would be required for really ancient type boilers that just fire up when
there is electrical power. Think old cast iron lumps.

Most modern boilers use method (2), as it allows most flexibility in wiring,
although some (particularly combis) use method (1).

Sounds good. Many thanks for your continued advice!

Dan

In message , Dan
Gravell writes
Christian McArdle wrote:

Every gas boiler ever made that uses electricity can support a programmable
thermostat.

Sounds good. Many thanks for your continued advice!

I've been using a programmable thermostat with my combi since it was
installed, works fine.

Re the problem with the timer. I had an integral (electronic not
mechanical) timer on mine . I used to leave I just set on all the time
with control via the programmable stat. Then earlier this year it
developed a fault and the timer would turn off, turning off the heating.
Since i never used it, I wasn't bothered about repairing it, so I just
remade the connections so that the supply to the boiler was then always
on.
--
Chris French, Leeds

Christian McArdle wrote:

Set the timer to be on 24 hours a day. Replace your room thermostat with a
programmable type. Then it doesn't matter that your clock is knackered, and
you have the heating controls in the lounge, where they belong and all the
advantages of a programmable thermostat, such as selecting a specific
temperatures for different times of day.

This presumes that the same fault doesn't prevent the 24h option from
working.


Thanks to all that have helped. I think I'm going to go the programmable
thermostat way, rather than just buying a new timer for the boiler.

I've rung around a few plumbers and they've all said it's one/two hours
work. I only want them to connect the base station to the boiler, I'll
sort the thermostat myself (it'll be a wireless one). So this basically
means about £100 labour, perhaps a little more, plus the part. So no
different to getting the boiler fixed then.

My next question is, is this possible for me to do, or do you need to be
Corgi registered? That's what Honeywell alluded to when I contacted
them. I have the good old Collins book but it doesn't give decent
instructions on how to fit these things, which might be telling.

Thanks again,
Dan

My next question is, is this possible for me to do, or do you need to be
Corgi registered?

It is a very simple job, not dramatically more complicated than wiring a
plug. There is no need for CORGI registration. However, exactly what will be
required will depend on the thermostat chosen and your boiler. Do you have
model numbers?

Christian.

Christian McArdle wrote:

My next question is, is this possible for me to do, or do you need to be
Corgi registered?


It is a very simple job, not dramatically more complicated than wiring a
plug. There is no need for CORGI registration. However, exactly what will be
required will depend on the thermostat chosen and your boiler. Do you have
model numbers?

I don't know any more than the fact that it's a Sime Friendly, I believe
there are a few "sub-models". I don't have a manual (any more),
something I want to chase up...

Thanks,
Dan

I don't know any more than the fact that it's a Sime Friendly, I believe
there are a few "sub-models". I don't have a manual (any more),
something I want to chase up...

Can you find the electrical terminals? Are there any markings? Are two of
the terminals linked together with a bent bit of wire?

Christian.

On Thu, 14 Oct 2004 15:20:06 +0100, Dan Gravell
wrote:

My next question is, is this possible for me to do, or do you need to be
Corgi registered?

Yesterday, I was shown written confirmation that the electrics of a
boiler are not considered to be within the Corgi remit for gas. This
was by the engineer for a large domestic appliance supplier.

The engineers are trying for Corgi registration and their employer
don't want to pay for them to do it.

So it seems, in their opinion, anybody can fiddle with a boilers
electrics.

Christian McArdle wrote:

I don't know any more than the fact that it's a Sime Friendly, I believe
there are a few "sub-models". I don't have a manual (any more),
something I want to chase up...


Can you find the electrical terminals? Are there any markings? Are two of
the terminals linked together with a bent bit of wire?

I'll have to get back to you tomorrow, as the boiler is at home and I
don't have newsgroup access at home (or rather, I haven't set it up).
From memory there is wire, (including a yellow/green one?) these are
connected to the pipes on the boiler.

Dan

In message , Dan Gravell
writes

My next question is, is this possible for me to do, or do you need to
be Corgi registered?

Absolutely not if you're competent

I came late to this thread, but it's all here in uk-diy

--
geoff

In message , Relict of EricP
writes
On Thu, 14 Oct 2004 15:20:06 +0100, Dan Gravell
wrote:

My next question is, is this possible for me to do, or do you need to be
Corgi registered?

Yesterday, I was shown written confirmation that the electrics of a
boiler are not considered to be within the Corgi remit for gas. This
was by the engineer for a large domestic appliance supplier.

The engineers are trying for Corgi registration and their employer
don't want to pay for them to do it.

So it seems, in their opinion, anybody can fiddle with a boilers
electrics.

It has nothing to do with opinion

The only requirement is "competence"

--
geoff

Christian McArdle wrote:

I don't know any more than the fact that it's a Sime Friendly, I believe
there are a few "sub-models". I don't have a manual (any more),
something I want to chase up...


Can you find the electrical terminals? Are there any markings? Are two of
the terminals linked together with a bent bit of wire?

I had a look last night. The boiler is boxed in which makes it difficult
to look inside, I can take the boxing off when I need proper access but
didn't have time last night.

I found where the mains goes into the boiler, is that what you mean? I
was looking at some manuals for more up to date Sime boilers which
contain details of all kinds of terminals in the control panel and
thermostat box of tricks.

If not I need to do more digging around in the weekend.

Ta,
Dan