Not sure how our heating system works

clutterbug_2

We've just moved into a new house and the last owners are un-contactable (not surprising considering the rubbish and bare wires they left!).

But we don't understand the heating system, other than how to turn it on and have it on timer.

It's run by oil and there are three separate bits:

A condensing boiler which is on ground level.
What we think is a heating cylinder on the first floor.
An expansion vessel just above the cylinder.
There is also a pressure pump.

A friend has said we don't need the cylinder on all the time, and that we can get almost instant hot water off the condensing boiler.

Coming from houses with combi boilers, I'm not sure the most economical way to heat the house (big 3 storey mid terraced victorian townhouse with original single glazed sash windows!).

Thanks in advance

Smiley_Dan

What's the model of the boiler? It should say on it.

You can only get instant water off it if it's a combi. Combi's aren't normally connected to hot water cylinders though. Otherwise, if it's a condensing system boiler, you'll have to use the cylinder.

clutterbug_2

Boiler is a mistral cbh3 25/26

The expansion vessel is a zilmet cal-pro

alleycat`

It sounds, on the face of it that you have a "regular" condensing boiler with a hot water cylinder.

Does it appear to look roughly like this?

http://heatweb.com/systems/files/sysdschematic.GIF

alleycat`

clutterbug wrote: »

Boiler is a mistral cbh3 25/26

The expansion vessel is a zilmet cal-pro

Manufacturer Mistral Boilers
ModelCBH 15/26
Contract Fuel Type Oil
Type Conventional
MethodCondensing
Flue Type Open or Room-Sealed
Fan Fan Assisted
Output (kW)15 - 26.4
Boiler ID
Manufactured From/To2007 - current


It's not a Combi.

On that basis i expect you will have a hot water tank, an expansion tank, a separate pump, some sort of diverter valve and hopefully a programmable timer that does hot water and heating desperately that looks roughly like the linked picture i attached.

Edit:- if its as described i have the same system (albeit mains gas) and i can run you through how we use ours.

thozza

clutterbug wrote: »

Boiler is a mistral cbh3 25/26

The expansion vessel is a zilmet cal-pro

The Home Heating Guide lists a Mistral CBH3 26/35 Efficiency, if it is similar to this then it is a conventional condensing boiler and will need a hot water cylinder:

http://www.homeheatingguide.co.uk/efficiency-tables.php?model=015341

If it has an expansion vessel, it suggests the heating is a sealed system, although it could mean that the hot water cylinder is pressurised, an make/model will confirm this. Is there any sign of header tanks in the loft?

These types of systems are explained on a leaflet produced by the APHC (Association of Plumbing & Heating Contractors)

http://www.aphc.co.uk/UNDERSTANDING%20CENTRAL%20HEATING%20SYSTEMS%20Dec13.pdf

It might be worth asking a plumber/heating engineer to take a look as it may require servicing, they would be able to advise how it functions, try the OFTEC website for an oil installer:

http://www.oftec.co.uk/

clutterbug_2

Thanks all.

There's a big black water tank (no lid) in the loft space between the first and second floor, nothing else that we can see. There is a thermostat downstairs and a programable timer next to the cylinder.

So, the cylinder needs to be left on permanently? It's been off since last night, as per friend's advice �� and we're still getting hot water and heating worked this morning.

Cardew

clutterbug wrote: »

So, the cylinder needs to be left on permanently? It's been off since last night, as per friend's advice �� and we're still getting hot water and heating worked this morning.

By 'cylinder need to be off' I assume you mean the electrical Immersion heater in the Hot water tank(which is usually a cylinder!)


Your oil boiler will(should) heat the hot water in the tank and you do not need to have the immersion heater on at all.


The timer should allow you to programme the times for both heating and hot water according to your personal requirements. This is a perfectly normal set-up.

alleycat`

Basically what Cardew says.
You need to be more clear about what you mean by "on".

If you mean an electrical switch that connect to the top of the tank then, yes, that should only be used in an emergency.

It's the equivalent of heating the tank in the same way a kettle element works.

It's not necessary for the Immersion to be working if the boiler is working correctly.

Typically setting the boiler timer to heat the hot water tank a couple of times a day is enough.