Moving from traditional boiler to combi, do you leave the pipeworks in the loft?

groovybug said:

@CBW I'm moving to combi so the issue was not about main fed cold/gravity fed hot. I'm asking normally when converting from traditional boiler to combi, do people move their pipeworks from the loft to under the floor? This has big implication for my renovation plan.

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What you class as traditional is still a current model. Combi is all in one boiler as complexity is what will make sure you have no hot water or heating when the boiler fails

Have you considered replacing the hot water cylinder with an unvented cylinder( you can lose the cold water storage cistern) and a heat only or system boiler, even combi boiler for heating ( combi supplying water to kitchen/ utility). Pressurising the system may reveal weeps in the system so keep it open vented.

Alec_t said:

... but the sytem components are physically separated, generally more get-at-able, and probably a wider choice of spares. Most won't need a Gas-Safe registered engineer for maintenance.

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Exactly. The various bits are still there, just all together, in a combi.

fixitflav said:

Exactly. The various bits are still there, just all together, in a combi.

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So, in your opinion, would you say a combi is easier to repair and maintain?

Guys, sorry I don't want this to be the discussion about combi vs traditional. Could we please return to the original question? Thanks

DP said:

So, in your opinion, would you say a combi is easier to repair and maintain?

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No, harder. The pump and doverter valve are is less accessible. So is the expansion vessel, which may not be fitted on a conventional system, F/E tank instead.

groovybug said:

Could we please return to the original question?

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There are no set rules, it is completely up to you.

groovybug said:

Guys, sorry I don't want this to be the discussion about combi vs traditional. Could we please return to the original question? Thanks

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To be honest, I have read your post many times, and I have no clue what you are actually asking

groovybug said:

Guys, sorry I don't want this to be the discussion about combi vs traditional. Could we please return to the original question? Thanks

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It's fairly simple IMO. (If you insist on a combi!) the CH flow and return of the combi will be tee'd into the rad circuit, at the most convenient point depending on the house layout. The combi HW outlet tee'd into the HW pipework. Any pipework and tanks left redundant can in principle be removed.

Frankly, OP, you seem to know all the answers anyway.

An Unvented cylinder is head and shoulders above a combi, but you re not interested in proper advice.

You have already worked out that you can re-route the pipes, and only an idiot would think that lots of pipes running to the kitchen via the loft is a good idea. If you are going to have a combi in the kitchen then you have to have mains there. Ergo, extend the pipes to the sink and bathroom. The sink should be off the mains anyway, and probably is. . The heating pipes have to emanate from the boiler, so, again, they have to get there. So, really, your question is a bit weird.

And pipes can either go up or down from most boilers, to suit circumstances.

Now, ignore the next bit, as you are not interested, but another reader maybe: Combis are prone to breakdown, and once broken down, you have no HW or CH. Most folk can manage without the heat, but HW is something else. A cylinder provides the opportunity for back up ie an immersion heater.

But, as said, be aware that some items may need modifying or replacing due to increased pressure.

The typical experience of a combi customer is that they are deliriously happy. for about 2 years, whenupon they get hacked off with the water cycling between hot and lukewarm. Generally a result of a dirty system, even though they have paid for a powerflush. The said PF is often carried out with the new boiler changeover, and when it is a simple changeover the whole job is often completed in a morning. Which, frankly, is impossible. No matter how fast the fitter, you cannot speed up the chemicals.

@ianmcd @FiremanT Sorry for my somewhat ambiguous question, too much thinking out loud there.

My question is not about the boiler systems. In short, I'm asking whether I should re-run pipes under floor, or leave pipes where they are in the loft and just re-route a few.

Obviously it's tempting to leave them in the loft: quick and easy re-routing task, also they will be more accessible for repair/maintenance. Re-running underfloor is a big undertaking: new pipeworks, taking up all the flooring of kitchen and bathroom is not an easy task, and very costly. However there are benefits to do that (less heat loss, better pressure etc..). So I'm asking what would you do.

groovybug said:

@ianmcd @FiremanT Sorry for my somewhat ambiguous question, too much thinking out loud there.

My question is not about the boiler systems. In short, I'm asking whether I should re-run pipes under floor, or leave pipes where they are in the loft and just re-route a few.

Obviously it's tempting to leave them in the loft: quick and easy re-routing task, also they will be more accessible for repair/maintenance. Re-running underfloor is a big undertaking: new pipeworks, taking up all the flooring of kitchen and bathroom is not an easy task, and very costly. However there are benefits to do that (less heat loss, better pressure etc..). So I'm asking what would you do.

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If you do as I suggested in #23, I can't think of any reason why the pipes would need to go through the loft, unless the layout of your house lends itself to that route. Without knowing more details, IMO it's impossible to say.
And I still don't think a combi is your best choice!

post pics of exactly what pipes are in your loft, and where they go

ianmcd said:

post pics of exactly what pipes are in your loft, and where they go

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All pipes are in the loft. There is no pipe under the floor, except for main that also goes up to loft before going down to kitchen. Boiler is in the kitchen, HW cylinder is in a hallway cupboard.

groovybug said:

All pipes are in the loft. There is no pipe under the floor, except for main that also goes up to loft before going down to kitchen. Boiler is in the kitchen, HW cylinder is in a hallway cupboard.

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Are you in a bungalow?

If in a house, and "under the floor" is between going and first, how do the pipes get to the rads. How do your primary circuits get from Boiler too cylinder. All without going under a floor?

FiremanT said:

Are you in a bungalow?

If in a house, and "under the floor" is between going and first, how do the pipes get to the rads. How do your primary circuits get from Boiler too cylinder. All without going under a floor?

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Sorry I meant hot/cold water pipes. Yes the pipes to radiators are under the floor. Flow and return between boiler and cylinder also over the loft. I have the inverted boiler type with pipes going upwards.