1930s Semi Refurb - Part 2 of ... (Edition: Boiler/Water Tank Relocation)

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dirtychinchilla said:
I don't understand why you'd want a hot water cylinder
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Well, when talking unvented indirectly heated cylinders ;

Same pressure as a combi, ie if your mains pressure is good will be fine

Mine heats up 30mins a day and can afford showers twice a day for 2 adults.

Not limited to high kW output combo boilers (which is only necessary for heating instantaneous hot water and is inefficient/oversized for central heating)

Don't hear the "nyoooooooom" of boiler delivering hot water out the tap (and quicker to deliver it). Just have it running in the morning for 30mins while in bed (mine is in my kitchen)

Has the resilience (can be heated both electrically or by a boiler) - eg for solar installs can pass all excess to the cylinder
 
dLockers said:
I read this and ignored but then came back to it. Good question. It was mainly because I'd like to run the heating coil on electricity once I get solar. However, realistically that could be a long way off.

Chaps - should I just get a combi? I mean, the world is ending anyway, it'll save me a fortune in capital right now, and I can delete the tank.
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If you are planning to get solar, then that makes a great deal of sense. I have a colleague with solar panels who has an immersion heater (and an anti-stratifcation pump). He uses the excess electricity in the day to heat his water tank.

mattyg said:
So you can have hot water out of two taps at the same time?
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dLockers said:
This is probably valid however it almost ZERO instances where this happens (2 adults 1 child).
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There's something called diversity, which says what dLockers is saying. It's an extremely rare occurence typically.

I have a combi boiler at home and my wife and have never had an issue with drawing hot water at the same time. You just size it appropriately/
 
Buffman said:
Well, when talking unvented indirectly heated cylinders ;

Same pressure as a combi, ie if your mains pressure is good will be fine

Mine heats up 30mins a day and can afford showers twice a day for 2 adults.

Not limited to high kW output combo boilers (which is only necessary for heating instantaneous hot water and is inefficient/oversized for central heating)

Don't hear the "nyoooooooom" of boiler delivering hot water out the tap (and quicker to deliver it). Just have it running in the morning for 30mins while in bed (mine is in my kitchen)

Has the resilience (can be heated both electrically or by a boiler) - eg for solar installs can pass all excess to the cylinder
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I don't necessarily disagree with you, but you have to generate water at 60C for a tank. Without, you can go down to 45C because there's no legionella risk.
 
For me the mains advantages of a traditional boiler/HW cylinder vs combi are not having the boiler kick in every time you use some even a tiny amount of hot water, having a reserve of hot water so you'll never exceed the boiler's output (and power failures aren't an issue) and being able to use electric immersion in the event of boiler issues. I've always been able to fit mine in cupboards so get the added benefit of a warm airing cupboard.

In terms of cylinder, Megaflo are just an brand of cylinder and integrated expansion device. I prefer to get a general high quality unvented cylinder (mine has 25 year warranty) with a good size heating coil and a separate expansion vessel as they can be easily and cheaply replaced if needed.

On some modern boilers/controllers you can also run the HW cylinder at lower than 60C if desired, and once a week it will raise the temperature to 60C to prevent legionella risk. However I leave mine at 60C all the time as this means less hot is needed to mix with cold so increasing the effective usage of shower/bath temperature water. You also need a higher KW output for a combi, so a larger boiler and as its used more frequently and has the repeated heat up / cool down cycles it will suffer more wear.

For overall space usage a combi is great, but I think an unvented cylinder and standard boiler wins for other cases.
 
@dLockers, if you are refurbing a big chunk of your heating system, proper hydronic balancing is going to be essential. It's a thankless task with normal TRVs - they balance fine in full load, but as soon as you get to part load (i.e., a room has got up to temperature and the head shuts), the balancing goes out of the window.

At work well sell something called Pt40s and Rt40s that automatically balance your heating system for you. They aren't terribly cheap, but they're certainly worth it if you're going to be in the property long term.
 
Just had a guy I trust visit. He reckons that putting both the boiler and the tank in the loft is the best idea. It'll be just as much pipework to get it "there and back" than to just run a new water main and a new gas pipe up there.

Fingers crossed the quote isn't $lol...
 
Guys,

I am really having an existential crisis on this whole boiler thing.

I really want a new system boiler and vented cylinder, but that is because of a pipedream of having solar. Now realistically I can't afford either the boiler or solar :cry: So I am now questioning whether an interim (read: probably the next 10 years) is to go for a neat and tidy combi boiler.

Then regardless of uvented+system/combi, my radiators are all 40+ years old. They are absolutely massive in the two front rooms with exposed pipework and drops from the ceiling. Proper 'bodge'.

So I phoned my trusted boiler serviceman today and he said he can get my Potterton working, so at least I'll be toasty this winter (albeit at a mega $$ I expect) which then made me think well, that'd at least buy me time to get to summer, rip all the radiators out, run a new downstairs circuit and terminate it where I want the rads to go forevermore, and sort out the upstairs circuits - then get the boiler man in to swap the system out.

Decisions, decisions... Lucky I am skint so need to be careful :D

Edit: The £6k quote I got is pretty reputable but I know they just sub-con the work out to the lowest earning tradesmen so I am a bit cautious about choosing them. That also doesn't include any rad-work so I'd still need to do a major job in re-running pipework.
 
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Just one thought from me - if you have oversized radiators then you may be able to exploit their size to run lower flow temperatures. However, my parents also have giant radiators but they are single skin, so they aren't very efficient. Perhaps you have the same.
 
dirtychinchilla said:
Just one thought from me - if you have oversized radiators then you may be able to exploit their size to run lower flow temperatures. However, my parents also have giant radiators but they are single skin, so they aren't very efficient. Perhaps you have the same.
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Yeah they are single skin and the plumber noted something about "missing a modern feature that helps improve efficiency".

Really need my head banging lads! Please can someone tell me what to do :D
 
I was thinking about your situation. Personally, I'd go with a combi. I'm still not convinced that instant hot water is a good enough benefit to having a cylinder. The disbenefit of having a cylinder is that you nee da higher DHW temperature. So I would go combi personally.

You have a great opportunity here to have a super efficient heating system, which is what people in the UK need right now. If I had that opportunity, I'd go all out. Oversized radiators, small pipework, low flow temperature, high delta T, good TRVs etc
 
dirtychinchilla said:
I was thinking about your situation. Personally, I'd go with a combi. I'm still not convinced that instant hot water is a good enough benefit to having a cylinder. The disbenefit of having a cylinder is that you nee da higher DHW temperature. So I would go combi personally.

You have a great opportunity here to have a super efficient heating system, which is what people in the UK need right now. If I had that opportunity, I'd go all out. Oversized radiators, small pipework, low flow temperature, high delta T, good TRVs etc
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Would you ever consider air surce heat pumps?
 
jonneymendoza said:
You.

vs a combi boiler?
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I would consider one if I had the money. As dLockers says, they're very expensive. If I was planning to be in a house for the next 30 years then I think it would be a worthwhile investment, particularly when paired with solar. But the cost is currently so high, including adapting your existing heating system, that for the house I'm in now it's not worth it. And I can't afford it :)
 
jonneymendoza said:
Probably little benefit?

I mean if costs wasnt a factor? Would you? or is combi boilers still more sustainable than air source heat pumps?
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If I had the cash then for sure. But even £6k for a standard setup is a tough pill to swallow. Unfortunately I have bought my house at the peak of the market (next door paid £120k less) so I can't remortgage to release the capital to do the work in a "one-er".
 
Yeah more efficient, but only after you've ripped out all your old radiators and massively upsized them, fully insulated the entire house and plugged all gaps and installed air conditioning because the house now gets so hot in summer. I'm not sold on heat pumps myself.
 
200sols said:
Yeah more efficient, but only after you've ripped out all your old radiators and massively upsized them, fully insulated the entire house and plugged all gaps and installed air conditioning because the house now gets so hot in summer. I'm not sold on heat pumps myself.
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Insulation works in two directions, remember. In the winter it'll keep heat in, and in the summer keep heat out.
 
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