Is there any websites anyone would recommend which shows you step by step guides to installing central heating. My brother wants to fit it and I've said I'll help. Done some plumbing before, few bathrooms and kitchens so feeling pretty confident that we could do it without any leaks but no idea where to start.
One thing we wont attempt is to fit the boiler to the gas or any pipework involved in that side, Mr Gasman can do that.
He can buy a kit which has a boiler, 7 radiators, copper tubing etc for £750. Is that a fair price or is he better off going to one of the sheds?
Unfortunately I never found one website that covered everything I required, so I ended up spending months researching and planning. Perhaps a little OTT but I got it done in the end; and I got it done properly and as I wanted.
You need to start by calculating the heat requirements for each room. Various web sites and tools do this, but by working out the BTU requirements you can calculate the size of radiator you require for each room. Once you have done this, you can calculate the size of boiler you require. Most gas fitters prefer to purchase the boiler themselves, and this is a good idea. ANY problems with the boiler, and you can you straight back to the and it is there responsibility completely. Purchase it yourself and you have mixed responsibilities. They are likely to get it for the same price as you anyway.
As someone else has said =A3750 sounds cheap for the whole lot. Don't skimp on the boiler; get something good quality, and that exceeds your current requirements. Also, because you are doing it yourself, consider purchasing radiators that you like the look of, and suit the room size and its aesthetics. No point getting cheap, bog standard rads, unless you are purely trying to save money.
Next work out where you want the boiler and the radiators. It's not essential to have rads under window, but it can help to cut down on cold drafts. Then trace the pipe work from the rads back to the boiler in the shortest or most convenient route. Do check the direction of floor beams (get in the way of underfloor piping), the ease of taking carpets and flooring up. Decide whether you want to use microbore piping or standard. Little benefit either way. I prefer the look of
15mm exposed piping to microbore, but that's just a personal pref. You will use more microbore pipe than you would standard 15/22mm.
Avoid exposed plastic piping, and my preference was only to use it when absolutely necessary (awkward bends, inaccessible places etc.) I would try to use copper whenever possible. It was my personal preference to solder as many joints as I could. They feel more reliable than compression and push-fit. Avoid push-fit on plastic piping at all costs.
Also bare regulations in mind. TRVs on all rads except the bathroom and the room in which you have a thermostat. You must have a room thermostat. Ensure all copper piping is earthed; if you have runs of plastic, the copper on either side must be earthed because the plastic breaks the continuity. Have at least one drain off valve in an easily accessible place (as low as possible) over a floor that can get dirty and slightly damp.
Most importantly, enjoy it. It's great fun. Time consuming but relatively easy.
I've just installed a CH system into a barge. 19kw pressure jet oil boiler, 13 radiators in a sealed system. Used Speedfit for most of the piping, but copper where size of corner joints is important - around the boiler etc. System filled with 40% antifreeze and hot pressure tested to 3 bar. Speedfit joints are great - no mucking around with a blow torch in confined spaces and with current copper cost plastic is cheaper. Less heat is also lost through plastic pipes than copper. System works brilliantly and I am just making my OFTEC badge to put on my overalls!!
Well, it's not quite that simple. You must have controls which prevents the boiler from firing and keeping a primary circuit warm when there is no call for heat. This is most commonly done using a room thermostat, but you can implement this some other way if you want to.
A room thermostat is not strictly neccessary. On my installation, I have not yet got around to installing a programmer/roomstat and cylinder stat. The room stat connections on the boiler have been connected through a switch, when made it simulates the room stat. All the rads have TRVs, so close when room is at temp. There is also a bypass shunt to stop the pump working hard against shut TRVs. The boiler thermostat is set at approx 80C, with a safety max thermostat fixed at 90C. When the boiler main switch is made the pump also circulates, when the room stat switch is made the boiler heats the coolant to 80C and then shuts off. Hot coolant continues to circulate through the system until the coolant temp falls to approx 65C - and boiler fires again. When boiler stops firing, the temp inside the boiler continues to rise for a few mins - there is a lot of heat absorbed in the boiler metalwork. The boiler heats up the coolant considerably faster than the rads can cool it - so the duty cycle is quite low even in last week's cold weather. As easy refinements I could put a timeswitch on the boiler main power so that the system only comes on say twice a day - morning and evening etc and a delay off relay on the pump so that it continues to run for a few mins at the end of each heating period.
I'm having a bit of difficulty seeing how this setup complies with Part-L of the building regs. True there are many many systems like you have but they (AFAIK) don't comply.
Such a setup is no longer permitted, as it violates the very point you are following up. You are right that you don't have to have a thermostat, but you do have to have something which shuts off the boiler. This could be a flowswitch on the radiator circuit after the bypass, so the boiler can't fire up when all the TRV's are closed, although that does require the pump running continuously when the heating is on.
In my experience the majority of installers do not understand that this is not necessary either. This is a real problem when they propose palpably stupid control systems.
Luckily the system is on a barge - so Part L does not apply! The whole point of a bypass is for if and when all TRVs are closed - not likely with the current wx?
Once the programmer, room stat and 2 cyl stats for the 2 hot water tanks are wired up, there will be ample devices to shut off the boiler. The system also does not have a 3 way valve, the hot water tanks are taken off the supply/return pipes just like a radiator - and are also heated when the engine is running, and might be heated when the generator is used - but that will need a HWT with 3 coils. However, HWT do not have TRVs or equivalents, so there is always a path for the pumped coolant - just like having a bathroom radiator.
Yep. One was telling me that it was law that a room stata and by-pass had to be installed. Expaining the "control interlock was like talking to the wall.
You need a "control interlock". This switches out the boiler when no heat anywhere in the house is called. So this usually means one rad open and an auto by-pass and room stat in the rad with no TRV.
The Baxi 133 HE Plus and a few other Baxis have built-in flow switches meaning TRVs all around and no wall stat as the burner is switched out when the flow is below a set rate.
You can fit your own flow switch and TRVs all around and a Grundfos Alpha auto modulating pump. The flow switch would need to be adjustable, or have an adjustable by-pass around it, to set the right cut off flow, to switch out the burner when below the minimum flow the makers state through the boiler. This way is best with a condensing boiler as a by-pass returning hot flow water to the return prevents condensing and lowers efficiency.
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