Replacing my back boiler/central heating system

NoNameNoNumber said:
Well the boiler selector suggested an 837 exclusive I guess I made some false assumptions... I think the 831 could be a safe bet.
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Stick with the 831, the 837 has a built in water tank, not really needed, the higher 24kw rating of the 831 will benefit the hot water flow output slightly.
 
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Last week we had our old back boiler replaced, sounds like the same setup you have. It was a Baxi back boiler with a (hideous) fire place in front, hot water tank upstairs and tanks in the loft.

We've had a combi boiler fitted in the airing cupboard upstairs where the old hot water cylinder was. All that was done was all the old stuff ripped out and the boiler connected to exsisting pipework that ran up there, and a new gas pipe up.

All the rads had thermostatic valves fitted and were each removed to be flushed out (had barely been touched for 40 years!). Although it runs under pressure there's no reason why it should be a problem. Think we paid £2100 all in which I don't think is too bad all in all.
 
There will be 2 zone valves, one for downstairs and one for upstairs (plus one for the cylinder if you don't have a combi) with separate controls, so the flow and return pipework for both are completely separate up to the zone valves.

Have a look at Gloworm boilers too, same company as Valiant but can be more reasonable and do (did?) have 5 year guarantees.
 
andy_mk3 said:
Last week we had our old back boiler replaced, sounds like the same setup you have. It was a Baxi back boiler with a (hideous) fire place in front, hot water tank upstairs and tanks in the loft.

We've had a combi boiler fitted in the airing cupboard upstairs where the old hot water cylinder was. All that was done was all the old stuff ripped out and the boiler connected to exsisting pipework that ran up there, and a new gas pipe up.

All the rads had thermostatic valves fitted and were each removed to be flushed out (had barely been touched for 40 years!). Although it runs under pressure there's no reason why it should be a problem. Think we paid £2100 all in which I don't think is too bad all in all.
Click to expand...

Yeah I think that sounds reasonable tbh. I did consider doing exactly as you've done but a) I don't really want the boiler in an upstairs bedroom and b) the existing pipework/rads are absolutely full of silt and crud.
 
Crude paint example:

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Different thickness lines being 15/22 mm pipe.

Returns can be communal as long as the flows are separate, although its best practice to keep them apart until as close to the boiler you can get to stop heat creeping where you don't want it (i.e. not like the drawing!)
 
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No they'll be external, part of the control system.

More commonly with combi boilers you just have the one zone for heating, so you only have one combi thermostat wired into the boiler directly to control the heating.

With 2 heating zones, the wiring is slightly different in that you need to control it externally so its wired similarly to a conventional/systems boiler, but with on-demand hot water.
 
I think realistically I'll run the new pipework and fit the rads but I'll leave the boiler and all of its connections to a suitable plumber. I'd hate to get any if it wrong :)

I've drawn up a schematic of what I think the loop should look like... I'll upload when I finish work :)
 
No radiator in the conservatory, make it a usable space in winter.
Is kitchen/diner going to be warm enough with just one radiator, & no radiator in bottom hallway.

Zone 2: I would run through bed 2 with 22mm pipe to bathroom, teeing off at start for master bedroom in 22mm, reducing down to 15mm, & teeing off in bathroom for bedroom 3 again with 22mm reducing down to 15mm.

Have you calculated radiator sizes for the rooms.
 
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No, it's only really a porch area.

Kind of an odd setup really as that's the front door, the path to the garden gate and driveway run to the right so I'm kind of unsure what to do with it... 9'9" square

I'll try and digest that and revise my drawing :)
 
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I also a strange size bottom hallway, fitted a small radiator there to warm the space, as it gets quite cold, & it makes the top landing cold,when using front door despite having a porch.

Also going fit in a week or so, a narrow vertical radiator, can't use any thing else as I only have a narrow strip of wall on the top landing available.
 
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Yeah I've calculated the rad sizes for the rooms, forgot to add on the drawing that it's NTS :P

I've forgotten the total BTU requirement though if that's what you were gonna ask!

Strange size as it's quite wide?
 
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