Condensing boiler probably kaput, replace or switch to combi?

NatNat77

Hi forum 

Looking for advice and recommendations please! 

So, our British Gas 330 boiler failed to come back on after a power cut yesterday. We have a gas safe engineer coming out tomorrow. From the label on the front it appears to have been installed in 2005 so it is pretty old, and from what I've seen online it could be an issue with the PCB which is likely to be too expensive to repair, if it can be repaired at all. The boiler is currently in our attached garage (detached 4 bed house with one bath and 2 showers although we will be adding an additional shower/bath in the nearish future). Rarely will more than one be used at the same time but we would like to be able to use taps at the same time someone is in the shower...

The airing cupboard is in a bedrooms upstairs and we were thinking of moving it into the loft anyway, when we build our extension, if keeping it was the better option, as it would create space to put a new staircase in to the part loft conversion we're planning.

We were also expecting to upgrade the current system and look at other measures such as external insulation and solar panels to improve energy efficiency etc but when we were doing the building works, however we are where we are!  So I'm wondering would we be better to just replace it with a new condensing boiler or should we switch to a combi, perhaps with some storage? I actually love having an airing cupboard but I'm happy to sacrifice it, as it'd be nice to get rid of the tanks in the loft and tbh the whole system confuses me.

But will a combi struggle to meet our needs and how hard/disruptive is it to switch? If we have a combi should we move it into the house or is it not worth it? Are combi boilers with storage any good? Any brands to avoid? I will obviously ask these questions of the engineer but would like some unbiased views/recommendations/advice in advance if possible!

Grateful for any advice really, thanks, Nat 

Typhoon2000

No not a Combi for a house with multiple bathrooms. If it’s going in the garage where you have space, I would suggest getting a regular boiler and spec your own expansion tank and pump according the your house and planned extension rather than a system boiler where everything is undersized and crammed into the housing to save space. I would suggest an unvented cylinder for hotwater storage, for mains pressure hotwater. It can go in the garage if you don’t want it in the loft.

Bendy_House

Agree with Typhoon - a combi will really struggle/fail to provide what you need. It WILL be affected by other taps/loos, unless - perhaps - you go super-dooper combi and your mains supply is awesome.
And if you want to add other energy sources - PV or solar- then a stored system is clearly the way to go.
So, an unvented hot cylinder, either in the loft (probably better for fast water delivery) or even in the garage with a new system boiler is probably best. Then either a couple of solar panels to add to the cylinder, or PV via an immersion heater, will help keep the tank topped up.

Bendy_House

What's your mains pressure & flow like?

Bendy_House

Oh, and refurbished PCBs are cheap - £35-ish - and should last years. Usually only a single component fails, and - once replaced- the board is good to go. Just in case you want to stall your decision for a year or so.

NatNat77

Thanks both, that's very helpful! If it's unfixable perhaps we keep the arrangement we already have with a replacement boiler but take the opportunity to move the tank into the loft, if it's reasonably feasible. I believe it is an unvented cylinder that we have already and water pressure is great. Some of it may be old and worth upgrading though. 

I'm not looking to save space necessarily but moving the tank into the loft would enable us to put stairs in their place, for access into the loft conversion we're planning, because as it is we're struggling to do that.

It would be good if it can be fixed for now though as our works involve replacing the roof tiles so we can't look at solar panels just yet unfortunately. But I love the idea of using solar to top up the hot water so whatever we get will need the capability to do that and be as future proof as possible 😁

NatNat77

The engineer has been and has ordered a part, so it can be fixed! He also said a combi boiler would be no good for us and recommended a system boiler with a megaflo tank, so we can get rid of the tanks in the loft. Any thoughts or experience with those anyone? 🙏

NatNat77

This is what my airing cupboard looked like a few weeks ago. Now we have no power to it but thankfully the immersion heater is working so we have hot water! Excuse the mess 😂

Bendy_House

NatNat77 said:

This is what my airing cupboard looked like a few weeks ago. Now we have no power to it but thankfully the immersion heater is working so we have hot water! Excuse the mess 😂

Nice job, NatNat - you are clearly a very talented plumber.

That is a 'VENTED' cylinder - ie it is at atmospheric pressure, and open to the air (via the large CWS tank in the loft). The flow from that is as good as the height of the CWS, so that's why they are fitted as high as possible in the loft.

Your plumber recommends an 'unvented' cylinder, and the 'Megaflo' is the most well-known make - it's almost like calling a vacuum cleaner a 'Hoover'. The Mega will be mains-water-driven, so will only be as good as your mains supply, which he will/should have checked.

And you can get versions which 'lay on their side', so will fit into restricted height spaces like lofts.

Sounds like the ideal setup.

BUFF

Bendy_House said:

Agree with Typhoon - a combi will really struggle/fail to provide what you need. It WILL be affected by other taps/loos, unless - perhaps - you go super-dooper combi and your mains supply is awesome.
And if you want to add other energy sources - PV or solar- then a stored system is clearly the way to go.
So, an unvented hot cylinder, either in the loft (probably better for fast water delivery) or even in the garage with a new system boiler is probably best. Then either a couple of solar panels to add to the cylinder, or PV via an immersion heater, will help keep the tank topped up.

A "super-dooper" storage combi will work for multiple outlets if you have the supply for it (a Worcester Highflow 550 will do 25l/min at 30C rise). My Worcester Highflow 440 has been extremely reliable since installed over 13 years ago & it's also very quiet.
Were you to be installing in your garage then noise probably not an issue but they also tend to be floorstanding which may be. Viessmann also do a similar, well-regarded product.

However, like others I would suggest going to a condensing system boiler with an unvented cylinder that will let you  also use solar in the future (make sure that you specify this at the time to avoid a possible, expensive mistake). As already mentioned Megaflo is a brand name & other equally good/ better & worse exist.

& whilst you are at it get load/weather compensating controls & a magnetic filter for your CH too if you don't already have these.. 

Bendy_House

Yes, a super-dooper combi coupled with a pumped accumulator would certainly do the job to more than one outlet at a time, regardless of how good/poor the incoming mains is. But, if there's room for an unvented, that is surely the way to go.