Megaflow or Combi???????

[manwithmission]

Just had a closer look at the PE pipe. I’ve only got about 5” from ground before stopcock & didn’t want to damage the lagging too much, so I’d just guessed. I’ve now measured it (best I can) at 28mm OD.

I’m not sure if the boiler has life in it. It’s 12 years old. I don’t know what the norm is??? Knowing the builder, I imagine it’s designed to just about cover the size of the house & since I’ve extended 2 stories, I thought it might be under-powered??

The fitter who will do the job is not the same person who told me Combis were best. I don’t know him, but he just fitted my neighbours & I know he would only deal with a fully registered person & he definitely does his homework. When I spoke with the fitter yesterday, he seemed to think that the 170 was enough to cope with one bath & 2 showers, but if we had a 2nd bath (which we won’t), we’d need the next size up. Next door has 2 teenage girls & they’ve had the CL170 (only yesterday mind you), so I’ll have to ask how they’re getting on quickly as the guy said he would order mine yesterday.

 

[noonespecial]

Knowing the builder, I imagine it’s designed to just about cover the size of the house & since I’ve extended 2 stories, I thought it might be under-powered??

Is your house warm enough in depths of winter - if it is the boiler is not underpowered.

 

[manwithmission]

Is your house warm enough in depths of winter - if it is the boiler is not underpowered.

I would say it is, but we do have issues like some of the downstairs rads not getting hot enough & the boiler does seem to work hard, running through the night, which is a bit noisy right under my lad’s bedroom.

 

[corgiman]

it may well be unsized if you whack a megaflow on it, do the sums and ensure its butch enough to cope

 

[Handyman]

The only drawback to unvented is that you will still have a sodding great cylinder in the cupboard!

Assuming, of course you put the Megaflow in the cupboard. M-w-m might not realise that can install a sealed system cylinder more or less anywhere: In a cellar (like I'm going to), or in a garage, or in any vacant cupboard, and if convenient, near to the boiler.

The manwithamisson might like to consider putting a small radiator in the airing cupboard, (possibly run off the primary circuit), because modern cylinders are so well lagged, they don't lose much heat, so your hitherto nice warm airing cupboard would cease to be so. The small rad would be particularly relevant if m-w-m instals Megaflow cylinder elsewhere.

 

[noonespecial]

[/quote]

I would say it is, but we do have issues like some of the downstairs rads not getting hot enough & the boiler does seem to work hard, running through the night, which is a bit noisy right under my lad’s bedroom.[/quote]

But is your downstairs warm enough - because your rads are not getting as hot as you think they should be does not mean that your boiler is undersized - it could be the rads are oversized and they have been regulated down.

Harder the boiler works the better - each time a boiler cuts in and out you are losing money on standing heat losses through the boiler.

Why do you run the boiler through the night? Is it because the house takes hours to heat up in the morning when it is switched on? If it is not that and you just want a house which is warm at night then you will have to have a new boiler running in a similar manner. Would be cheaper to turn the boiler off at night and buy some bed socks and also some ear plugs for the lad

Also bear in mind that the modern boiler fans generally develop higher pressures and are therefore often noisier than their non-condensing counterparts.

 

[noonespecial]

[/quote]

Assuming, of course you put the Megaflow in the cupboard. M-w-m might not realise that can install a sealed system cylinder more or less anywhere: In a cellar (like I'm going to), or in a garage, or in any vacant cupboard, and if convenient, near to the boiler.[/quote]

Quite right (also in a roof void).

If so make sure it, the pipwork and control / safety devices are protected adeqautely from frost / freezing.

 

[manwithmission]

Some really interesting suggestions. I'm going to have a look at my neighbour's tank to see how hot it is. The idea of having it in the garage or roof space & a small rad in a big empty airing cupboard is is definitely of interest!

I think the downstairs rads not heating up is more down to bad plumbing design. I had thermostats fitted on all rads except the bathrooms, so I sould be able to control them, but some of the downstairs ones definitely don't get hot enough.

 

[noonespecial]

I had thermostats fitted on all rads except the bathrooms, so I sould be able to control them, but some of the downstairs ones definitely don't get hot enough.

Ah thermostatic radaitor valves - are you sure then that radiators are not getting hot enough?

Are your rooms warm enough?

It could be the TRV's are doing them job properly, keeping the rooms at the required temperature, reducing the water flow rate and thus reducing the surface temperature of the radiators?

 

[manwithmission]

Ah thermostatic radaitor valves - are you sure then that radiators are not getting hot enough?

Are your rooms warm enough?

It could be the TRV's are doing them job properly, keeping the rooms at the required temperature, reducing the water flow rate and thus reducing the surface temperature of the radiators?

I'm sure it's not. 2 rads in the same room, one boiling, the other cold! The plumber I spoke to yesterday (the one fitting his Megaflow) said he'd found some poorly designed pipework.

 

[noonespecial]

But are the rooms warm enough??????????

Yes or no?

 

[manwithmission]

But are the rooms warm enough??????????

Yes or no?

Well quite often no. It's a warm house, being fairly new & built with modern materials, but sometimes the downstairs rooms are cold (while the upstairs is boiling) & the rads don't seem to be doing their job.

 

[noonespecial]

ok then - if the rads are not hot and the rooms are not warm either the boiler is undersized, the TRV's are set too low/faulty or the water flow rate is inadequate. Which is what you situation is.

If the rads with TRV's are not hot and the rooms are warm enough then there probably is not a problem as TRV's operate by reducing water flow to the rads as the room temperature increases, thus reducing their surface temperature and thus reducing radiator output. Which it does not seem is the case in your property.

 

[Agile]

As no one has stated it clearly yet, only a person with a special CERTIFICATE to install unventeds can do so safely and legally.

Holders of the unvented qualification will have a photocard to identify themself.

Failure to use a qualified person will possibly end up with a dangerous installation and may give building regulation problems.

Tony Glazier

 

[ACOperson]

Well, I said: "...is that from a CORGI engineer who is qualified to install these?". A CORGI guy whose reputation is on the line won't install these if he hasn't got the certificate.