mainsfed heating system

[stanner]

I have the choice of two systems to install, a megaflo with a system boiler, or a glow worm ultapower sxi store boiler,boiler in kichen two bathrooms 3 beds over 3 floors. im worried about the flow on the glowworm if the two showers are running. any ideas. cheers

 

[ddraig]

The glow worm is a great boiler, I think its got the top rating under sedbuk at the moment, however whichever you want to install make sure you incoming main can deliver the required flow rate.

 

[clf-gas]

If you have good mains pressure, good flow and enough convenient space, then 180/200ltr unvented cylinder and almost any system boiler should do you fine.

 

[Agile]

Unless you have been hijacked then I would say that you have a choice of any system that you choose.

Would you like to explain why you think that you are limited to only two systems?

Tony

 

[bengasman]

another option would be a large combi, easier, quicker and less expensive

 

[stanner]

the place has been piped up for the glowworm to be fitted, but I have concerns that at the end of the day its still only a combi, flow rate of 12.5 as against 70 odd for a megaflo if the mains pressure is ok I suppose.are there any other options I could consider? the plumber is recommending the glowworm so maybe I should listen to him, but i've had bad experiences with combis in the past.dont want to make an expensive mistake

 

[mickyg]

but I have concerns that at the end of the day its still only a combi, flow rate of 12.5 as against 70 odd for a megaflo if the mains pressure is ok I suppose.

no not at all, you've got it wrong. Its 12.5 l/mins only after you have depleted the store. Thats after you've emptied 170 or 100litres of hot water, and even then its only 10min reheat. It won't actually drop to 12l/min either. Its just the figures they give are, 35c rise(delta T) at 12.5l/min.
It will run happily at anything up to 36l/min if im not mistaken, and I very much doubt you have water flow rate that good to your house.

BTW what good would 70l/min be? you would empty a 200l tank in 3 mins!!

 

[ddraig]

but I have concerns that at the end of the day its still only a combi, flow rate of 12.5 as against 70 odd for a megaflo if the mains pressure is ok I suppose.

no not at all, you've got it wrong. Its 12.5 l/mins only after you have depleted the store. Thats after you've emptied 170 or 100litres of hot water, and even then its only 10min reheat. It won't actually drop to 12l/min either. Its just the figures they give are, 35c rise(delta T) at 12.5l/min.
It will run happily at anything up to 36l/min if im not mistaken, and I very much doubt you have water flow rate that good to your house.

BTW what good would 70l/min be? you would empty a 200l tank in 3 mins!!

Yes Mikyg is right, the Glowworm boasts being able to deliver around 170lts of hot water before switching to full combi (instant) mode, this is done due to its thermal store, so you should find that even on an excellent flow rate it will satisfy most peoples needs, however as already stated check you incoming flow rate.

Also remember, even though you have had bad experiences with combi's in the past, you will still need a new boiler to run the Megaflow, and all modern boilers can suffer from similar problems as combi's when it comes down to electronics ect

 

[BigBurner]

If you have good mains pressure, good flow and enough convenient space, then 180/200ltr unvented cylinder and almost any system boiler should do you fine.

But cost an annual service charge just for the cylinder alone and the boiler extra, so a no, no.

 

[stanner]

Thanks very much for your helpful info,I think I,m going to have a go with the glowworm, but will double check the mains pressure as advised. once again thanks very much.

 

[BigBurner]

Yes Mikyg is right, the Glowworm boasts being able to deliver around 170lts of hot water before switching to full combi (instant) mode, this is done due to its thermal store,

It has an unvented cylinder not a thermal store. The bumph says it heats the stored water directly. It does not. It heats the water in the cylinder indirectly via plate a heat exchanger and bronze pump. This method of re-heating the cylinder can be done on any direct cylinder and reheats v quick indeed and cheaper than using large indirect coiled cylinders - a smaller cylinder can be used.

The good thing about these one-box combis is that you do not have a separate service charge for an unvented cylinder. The service charge for the boiler incorporates the unvented cylinder controls too.

Also remember, even though you have had bad experiences with combi's in the past, you will still need a new boiler to run the Megaflow, and all modern boilers can suffer from similar problems as combi's when it comes down to electronics ect

Yep.

It is best to go for the weather compensation option on this boiler and fit a Magnaclean on the heating return pipe.