Unvented cylinder - what size?

[rrrrachel]

Hello,

We are replacing our (awful) Gledhill Boilermate thermal store with a new Potterton Precision boiler and Gledhill unvented cylinder. I'm totally clueless and just wanted to check that the size of cylinder we've been quoted for (180l) will be enough for our needs.

There are just 2 adults in the house, soon to add a baby, and possibly another in future. We occasionally have overnight guests. We have 2 bathrooms so occasionally use the 2 showers at once. More often we'll use the same shower 2 or 3 times in a row. (Water pressure is good and showers longish!)

I sometimes have a bath, but only in an evening when no other showers/baths are being used.

Will this be OK? Does it start to refill/reheat immediately, and how long would it take to replenish the HW?

I believe it will have an immersion switch too - if we run out of hot water and hit the immersion switch how long would it take to heat up enough for a generous shower? (It's a while since we had anything other than a combi or Boilermate).

Just wondering if it's worth upgrading to a 210l - not sure of difference in cost (and size re. the cupboard!)

Thanks,
Rachel

 

[ScottishGasMan]

Personally I'd future proof it and go for the 210 or 250lite version, showers dont use as much hot water as you might imagine, but one after the other and with a couple of little ones later on you might be thankfull you went for a larger one, for what presumably wont be a huge deal more money.

The cylinder wont start to reheat the moment you use it, it will have to drop temperature a bit first before it starts, and then your boiler may be heating the radiators at the same time so it may take a bit of time to get back up to temperature, and certainly cant reheat as fast as you can use it so a little bigger again may be worth it.

 

[ScottishGasMan]

http://www.gledhill.net/documents/Spec_103_Stainless_Lite.pdf

 

[PotatoHead]

I'd agree and go around 200 litres.

On a side note, I'm assuming British Gas are doing the fitting, have you compared the quote with a couple of local gas engineers?

 

[rrrrachel]

Thanks for the advice, I'll see if we can upgrade to 210 or 250.

It is BG. Yes, we got 3 independent local guys round to quote too, and surprisingly (having expected a massive difference) BG weren't hugely more. We also had a lot more confidence in the guy quoting - he was much more thorough especially with regard to changing the flue exit route and the water discharge from the UV cylinder. We're in a 3-storey terrace and the boiler and cylinder are both in the middle of the house so it's involving some floors up and minor building work. The other guys were a bit casual about what exactly they would do and how it would be left.

 

[PotatoHead]

Bear in mind an independent installer will offer 7 year warranty on boiler/cylinder, I think BG give one years free Homecare, without any other warranty. I don't know many people fitting Pottertons, probably for a good reason.

I'd also say the salesman from BG isn't the doing the fitting, it may very well not even be a BG employee, just a subbie - might not be a bad thing though. (I've heard tales of people going with BG, then the boilers fitted by a subbie who also came out to give a quote in the first place!)

With all that said if the independent installers were lazy/half arsed with their quotes then go with BG.