Talk to me about boilers

Almo

I don't know a great deal about boilers I'm afraid, so please bear with me.

We are looking at buying a 60s house which we've viewed quickly. According to the agent, there is a back boiler downstairs and upstairs (in the room directly above) is a water tank. When OH looked in the loft there was 'something water related' (his words) up there. The agent was one of the Saturday viewing people and didn't know a great deal about the house.

Does this sound like a likely set up? We are assuming that whatever is in the loft is an original gravity fed hot water system (it looks old) that is no longer in use and what now happens is that water is heated by the back boiler and pumped up to the hot water tank.

I believe we'd need to replace the boiler (and remove the water tank?).

Any feedback gratefully received, and obviously if we get to the point of wanting to buy the house we will take professional advice, just trying to get my head around things now - I am used to single storey houses in a country far away!

ValHaller

Tanks in a loft indicate a vented hot water system. This may be gravity circulation or it may be pumped. The heating is almost certainly pumped but might just be gravity circulation.

There is no automatic case to get rid of a back boiler. Every case should be judged on its merits. Back boilers work fine in fully pumped systems, although they can be poor for gravity systems if the boiler is not directly under the hot water cylinder - usually found in an airing cupboard upstairs - a reason for judging each system on its merits.

The usual alternative is a combi boiler. People say 'It's a combi, it is wonderful, you get hot water whenever you want'. Which leaves me quite nonplussed. The combi I have does not deliver when mains pressure is low. In the previous 2 houses I had back boilers which I converted to fully pumped and I had hot water when I wanted it to a far higher standard of supply than my present wretched despised combi

Almo

Thanks very much ValHaller. So does it sounds like all three elements might be in use?

The hot water cylinder upstairs is not directly over the back boiler, it's perhaps a metre to the side. If you'll excuse the really stupid question, does the back boiler just generate heat which is pumped upstairs to the water cylinder?

ValHaller

Almo wrote: »

Thanks very much ValHaller. So does it sounds like all three elements might be in use?

3 Elements? Fire and Water. I suppose it should be Earthed

Almo wrote: »

The hot water cylinder upstairs is not directly over the back boiler, it's perhaps a metre to the side. If you'll excuse the really stupid question, does the back boiler just generate heat which is pumped upstairs to the water cylinder?

The back boiler will transfer heat to the cylinder by either gravity circulation ie water convection or it will be pumped. You will need to inspect to be sure. If you see a pump, this is to be expected for the radiators - you will need to inspect more closely and see how it works. Sometimes there is an extra pump for domestic hot water. Sometimes there is a motorised valve on a pumped circuit. In either of these cases the hot water system is pumped. Otherwise it is gravity circulation. It will probably be OK with just a 1 metre horizontal offset, but if the boiler has life in it, then it may be worth converting to fully pumped.

Almo

I meant the thing in the loft, the water tank/cylinder thing and the back boiler!

Last house I owned the hot water system wasn't even inside the house so this business of things behind walls/in cupboards/in the roof is totally alien to me.

keystone

Further to Val's description schematically this:



is a gravity HW and pumped CH system where 1. is the boiler, 2 the HW cylinder, 3 the feed and expansion tank, 4 the cold water storage tank and 5 the CH pump.

This, however;



is fully pumped DHW and CH. Notice that the pump also pumps the primary circuit through the coil in the cylinder and there is additionally a bypass (here its a valve - 6) although in some installations the towel rail in the bathroom is on the primary and acts as a bypass as well as keeping towels warm.

Only you can tell what you have by looking at it (or by somebody else looking at it). Physically it might not look exactly like the schematic of course. For example the F&E and CWST are frequently installed one above the other the F&E being higher.

Pics always tell a good story. If you could post a pic of the area including all pipework around your cylinder that should help.

Cheers

Almo

Thanks keystone, that was incredibly helpful. OH is going to the house tomorrow, I will see if he can get some pics.

macman

Isn't this fairly basic info contained in the house particulars advertised by the agent? The house will have an EPC, so surely this info is written down somewhere, even if the viewing agent is clueless?

ValHaller

macman wrote: »

Isn't this fairly basic info contained in the house particulars advertised by the agent? The house will have an EPC, so surely this info is written down somewhere, even if the viewing agent is clueless?

My EPC from a few years ago has nothing to say about what type of heating system {combi, fully pumped, pumped with gravity DHW} and I have never seen anything useful in house particulars beyond the basic fuel, radiators by room, perhaps a mention of a hot water cylinder if they know what one is and a mention of the location of the boiler. Oh, yes they tell you if it is a combi as though it is a Good Thing :rotfl::rotfl::rotfl:

keystone

Poster on here the other day whose potential vendor had said boiler was a combi, same had been written in the HBR and guess what - it was a system boiler.

Cheers