Loft Conversion ~ keeping Pumped CH system

[Kraken]

We're due to have a loft conversion shortly and the builder recommended a combi boiler because it would both remove the tanks from the loft, and facilitate the installation of the loft radiator(s) and shower.

However, as our standard pumped system isn't too old (perhaps 7 years), and we have a £350 power shower which would have to be replaced if we went with a combi, we're considering keeping the existing CH system.

I know we can add a shower / toilet / vanity to the loft room either by installing a coffin water tank very high in the roof (to maintain a head of water), or by using a negative head pump.

My question is about a loft radiator. Am I right in thinking the feed and expansion tank has to be above the highest radiator in the house? And will a standard pumped system be able to pump water upstairs to a loft radiator?

 

[Agile]

You can use any bathroom arrangement as long as its mains water powered with electric heaters.

Your CH will not go above the F&E tank. It should be easy to put the small F&E tank high up in the loft conversion so the rads can be installed in the conversion. generally the base of the F&E should be at least 1m above the top of the higest rads.

Tony

 

[Kraken]

You can use any bathroom arrangement as long as its mains water powered with electric heaters.

Are you suggesting intalling a separate electric water heater for the sink and shower in the loft space?

Wouldn't a negative-head pump be a better solution, or are there major downsides?

 

[Doctor Drivel]

We're due to have a loft conversion shortly and the builder recommended a combi boiler because it would both remove the tanks from the loft, and facilitate the installation of the loft radiator(s) and shower.

However, as our standard pumped system isn't too old (perhaps 7 years), and we have a £350 power shower which would have to be replaced if we went with a combi, we're considering keeping the existing CH system.

I know we can add a shower / toilet / vanity to the loft room either by installing a coffin water tank very high in the roof (to maintain a head of water), or by using a negative head pump.

My question is about a loft radiator. Am I right in thinking the feed and expansion tank has to be above the highest radiator in the house? And will a standard pumped system be able to pump water upstairs to a loft radiator?

A high flow combi is the best approach in your circumstances. The £350 power shower? Do you mean pump? When off the mains this is redundant ...and no noise so an advantage. The mixer will work off the mains - check.

A combis is a simple clean and uncluttered solution that delivers. Because the system is 7 years old, it does not mean you need to keep it. Go for the best solution which is not an old cluttered design

 

[Kraken]

A high flow combi is the best approach in your circumstances. The £350 power shower? Do you mean pump? When off the mains this is redundant ...and no noise so an advantage. The mixer will work off the mains - check.

No, it's an all-in-one thermostatic power shower, a Mira Event XS. It can only be run from normal pressure hot and cold water. If we went with the combi we'd have to bin that, and buy a thermostatic mixer bar.

I'm just not sure that the £2600 we've been quoted to install the combi ~ a high volume Worcester Bosch (£3600 from British Gas!) ~ is worth it, given the tanks could be moved cheaply and a pump installed for about £300.

That said, I have no problem paying the cash if a Combi is the best solution. I've just heard (and read on here) horror stories about expensive combi repairs, and the loss of hot water entirely in the event of a failure is not a welcoming thought.

 

[gas4you]

You haven't told us what boiler you have now. It may be able to accept a pressure vessel and convert the system to a sealed system if it has an overheat stat built in.

You could then keep your gravity HW side if you can get your cold storage tank high enough.

 

[Kraken]

You haven't told us what boiler you have now.

Can't see an exact model number on the boiler anywhere (it was fitted before we moved in), but the cover mentions its an Ideal Classic FF, and the manual is dated 1999, so I'm guessing it isn't any older than that.

 

[gas4you]

As far as I'm aware as this has an overheat stat you could convert it to a sealed system. Best to call Ideal and ask to make 100% certain first though.

You can then put your radiators up in the loft no probs

 

[kevindgas]

yes the classic can be pressurised. there was a top box made for it to house the pump and expansion vessel (not sure it you can still get them) it had a pressure gauge in the front of it as well

i would suggest a bigger pump though a 15/60 for up to 10 rads or a 25/55 if you have more than that

 

[tryitandsee]

Had the same scenario with added bedroom and bathroom loft conversion, three months ago.

All I can say is that I was dead against having a pump to push water up into the loft, I kept thinking the noise from the pump would be annoying, waking the whole house up in the dead of night etc. I was getting quite worked up about it with the installing plumber, in the end, I went with his advice. The result being a good quality stuart turner twin pump both hot and cold balanced supply from new coffin tank. Pump located in airing cupboard. Fantastic, can hardly hear or notice the pump, as airing cupboard filled with towels, sheets etc. deadening sound. Bath in the loft fills up really quickly and if a shower needs to be fitted later, no problem.

With regard to extending your central heating I wouldn't bother.
You can never balance the system that well, having to tweak downstairs rads in order to get it to flow upstairs or end up changing to a larger circulating pump. If your system works well..........leave well alone.

The new regulations for the loft conversion will mean fantastic insulation so just install thermostatic/timed electric dimplex heaters, run off the extended ring main. Most of the heat comes from down stairs anyway. The wet system means more to go wrong. Yes it will cost more to run the electric dimplex, but it's only pennies extra and probably only going to be two heaters at most.

One last thing, don't connect up the water supply to the toilet cistern in the loft via the new pump as I first did. (Water hammer and weird noises and unnecessary use of pump) That can be supplied by a branch off the cold main that's feeding your new coffin tank.

Sorry so long, just my thoughts late at night.

 

[Agile]

If you can pressurise the existing system or raise the F&E tank then you could have a small unvented cylinder in the loft conversion to provide mains pressure hot water to shower and basin.

Tony