?Back Boilers??

[Brian]

Over the years, I?ve heard the term Back Boilers - especially in the 60s and 70s but rarely since- but only had a vague idea that they are, in simple terms, a heating system which is tucked away behind (typically) a gas fire or, as I recall a relative having, a solid fuel fire.

Is my assumption correct, please?

Also, are such systems still available? If, for example, you bought a house with such a system could it be replaced with another Back Boiler or would it mean converting to a ?conventional? system.

[newshound]

Correct. Two or three sorts. I expect you can still get woodburners which have these as an option. And a similar (simple cast iron box) could be fitted behind an open coal fire. Finally, radiant gas fires using a normal chimney as a flue were available with two sets of burners, one to heat the water-filled box hidden behind and another in the front, heating ceramic elements to provide radiant heat. Rather low efficiency compared to a modern boiler, which is probably why they went out of fashion. They all tended to be used for DHW rather than central heating, with a gravity/convection system needing no pump. Perhaps posh people had them running C/H but I didn't know any in those days.

[Tim+]

A traditional back boiler was built into the back of an open fire and would heat water in the HW tank, relying on a ?thermo-syphon? to circulated the water to the tank. Needed wide bore pipes running as directly as possible to work adequately.

Basic produced a gas fired boiler designed to fit into and open fireplace. It was ?open flued? which is deeply frowned upon now for safety and efficiency reasons. These boilers were hidden behind an open gas fire on the hearth.

You wouldn?t replace ?like with like? as they?re obsolete and inefficient compared to modern condensing boilers.

Tim

[Brian]

Thank you.

When I was a youngster, we lived in two houses which had some kind of system which heated the water and two radiators ( in the whole house - one in the kitchen and one in the master bedroom) using the coal fire. I think there was some lever to divert the heat from the fire somehow.

I?m sure there was no pump.

I?m assuming the system which caused me to ask the question is more modern- probably gas based- but I can?t be sure.

[Brian]

Thank you.

At least my basic understanding was about right.

I can?t be sure they ran CH systems, at least not ?proper? ones.

We had a basic back boiler system in two houses I lived in as a youngster ( probably built in the mid 50s). They had two radiators - not exactly central heating- plus the coal fire.

[Theo]

Lived somewhere with a 1970s Baxi Bermuda until recently - plenty of others still around, especially in rental properties. They can be plumbed just like a regular central heating boiler - airing cupboard with cylinder, pump, valves, 1990s controls, S plan in my case. They're a very simple spark ignition, burner, heat exchanger - not much different from an open fire with some pipes in it really:

Most of them are open flue into the chimney with room air providing the oxygen. This makes the room cold since you need a sizeable air brick.

It never went wrong, the annual service was mostly just vacuuming out the dust.

Seems you can still get them, although the fire in front is now separate and electric:

Theo

[Tim+]

Gah! Autocorrect changed Baxi to basic but I?m sure you got my drift. Sounds like you had an original ?back boiler? when you were a youngster. Baxi gas back boilers were very common for a period but they needed to be pumped.

Tim

[jkn]

We still have one, although the 'open' front fire has been disconnected. I had to replace the main valve unit a couple of years ago (got a Gas Safe engineer in to do the final fitting & checking). Ours is C plan I think, just a pump for the radiators.

I keep expecting it to fail but it seems to keep ticking over. Main reason for not replacing it is the concommitant work involved, it sets in motion a chain of works which we really don't want to do 'just yet'...

As Theo mentions, yearly servicing is straightforward. I do most of the sweeping out myself and get someone to check pressures etc. I also have CO alarms, and a CO meter which I use occasionally.

[Roger Mills]

Well, I'm certainly not posh, but I installed a Baxi Bermuda in my first house in the late 1970's. This fitted into a standard fireplace, with a gas-fired cast iron boiler at the back and a gas fire at the front. The heat exchanger had two pairs of connections - one pair used for a gravity (thermo-syphon) hot water circuit and the other pair for pumped central heating, feeding about 8 radiators.

There was a similar boiler already installed in my current house when I moved in, but that was a fully pumped W-Plan system. The boiler became unreliable when it was upwards of 20 years old, and I replaced it with a conventional boiler in a different location in 1990.

[Steve Walker]

The gas boiler behind the gas fire at my parents' house definitely did both DHW and CH. They installed it themselves in 1972 and had it tested and approved by the gas board. It ran until about 2005, when they put in a wall mounted condensing boiler. For the next 5 years, both boilers were plumbed in and the old one could have been brought back into service simply by moving the pump from its current position to its old position, opening two valves and putting the fuse back in the spur powering the controls. Eventually it was removed as part of updating to a newer gas fire.

[Steve Walker]

The gas people tried to condemn my parents' one, as there was no air brick, no hearth under the fire and carpet running under and impeding airflow - until it was pointed out that they had inspected, tested and approved it when it was put in; the bottom of the fire had a solid metal plate and did not need a separate hearth; and it was directly supplied with air from a duct under the floor.

I think that my parents' one once needed a new "thermocouple".

[The Natural Philosopher]

That's what we had, a boiler behind a coal fire, which if left roaring for an hour would deliver a basin full of tepid water for the once a week bath. In general we heated saucepans on the gas stove instead.

Some multifuel burners and wood burners have back boilers as do Agas. But its a shit way of heating water.

[The Natural Philosopher]

Depends what you call a proper one.

Anything that prevented water freezing inside the house was central heating

[Jon]

Yes, we had a backboiler behind the coal fire in our living room and we would burn drift wood from the beach....free piping hot water for the bath and sinks.

[Brian]

All relative really. Probably a radiator in most rooms or at least the main ones and probably pumped.

We had two radiators I don?t recall ever getting even warm. I seem to recall plenty of hot water for baths etc but I think we had an immersion heater as well. It was 50 years ago so ?.

[Brian]

I certainly remember people mentioning back boilers and, in particular, an aunt & uncle having one fitted with a smokeless (coke) fire in the late

60s. Plus we had some kind of system which has heated via the coal fire. The houses where built in the mid 50s +/-.

Certainly I don?t remember any maintenance on ours in either house. That said, I don?t recall the two radiators getting hot or even warm. There was hot water. I vaguely remember some level in the chimney which needed to be pushed / pulled to ensure the system worked. I will ask my older brother, he may recall.

My interest has been fired (no pun intended) as one of my daughters is looking at a house which has a back boiler. I?m assuming it is gas fired.

[Alan]

No, still available.But now more efficient and condensing. The link below is the first of a search, there are others.

[Martin Brown]

Pretty much. I have one on my log burning stove. Apart from making the side walls cool enough for some tar to condense on them it does a nice job of providing an alternative source of heating instead of oil.

Also exceptionally useful when there is no electricity since it can still heat the hot water and master bedroom by convection even with no pump running. They are somewhat out of fashion now since incompatible AIUI with modern configurations of heating system and boiler.

Power output has to be restricted wihtout the pump or it would boil!

However, the astronomical price of oil may change that.

It could but you would have to find the right heating engineer prepared to do the extra work needed to incorporate it into a modern CH system. Most just want to disconnect and fill a back boiler with dry sand these days. IME 4 out of 5 of them said it was "the only way to proceed".

[Andrew]

Hundreds of thousands of new houses built in the 60's and 70's were fitted with Baxi Bermuda back boilers. These had a 12Kw? cast iron heat exchanger with a gas burner and rudimentary controls fitted inside a dummy chimney breast and typically with a flue rising up about 4 feet then into a 45 degree angle block that was the base of a column of class 2 flue blocks that were the same 100mm depth as a standard block. Then another 45 degree exit block in the loft connected to a special ridge tile. Hanging in front of the back boiler was a

6Kw radiant gas fire.

Both houses I have owned had one of these. They were C plan because the hot water cyl was heated via a 28 mm gravity loop, and a normal pump connected to another pair of heat echanger tappings and fed the rads. This meant the hot tank could exceed 60C when the CH was in use because the only control was the boiler internal stat when the room stat was calling for heat.

The 'cheaper' 2 bed terraced houses near me (1977/78 built) only had the back boiler, hot tanke and gravity feed and radiant fire. Full C/H with rads and pump was an extra £500 from what I remember.

You can tell which (first) owners paid the extra £500 because the downstairs pipes were buried in the screed, while those that were retrofitted have pipework along the skirting.

[Andrew]

+1

Mine never went wrong. If the boiler thermocouple failed it was an easy replacement. BG scammed huge numbers of people into ripping theirs out using the "We cannot get parts for it" lie.

The main problem was that after 2002 they did not comply with Part L because they could be re-engineered as condensing boilers. Baxi did have a replacement but I thought they dropped it because of poor sales.

The actual Baxi website no longer lists the one you have linked to. Maybe there is a lot of unsold stock ?.