F&E tank for a megaflo?

Had a couple of plumbers around to give me a quote for a megaflo. One plumber mentioned that I would need an F&E tank for the heating particularly as one of my options is to retain the old boiler but the other plumber said nothing about it and it does not appear on his quote.

Does a megaflo need an F & E tank fitted for the heating in all cases or only if an old boiler is being retained. If not where does the expansion go?

Reply to
PC Plod
Loading thread data ...

It's got nothing to do with the megaflo per se. That will let you loose the Cold Water Storage tank, if you wish.

The F+E tank is to do with the boiler.

If the existing boiler has an open vented primary, it will already have a F+E tank. It will be a smaller tank, usually located close to the larger Cold Water Storage tank. If you retain the boiler, you retain the F+E tank.

If you replace the boiler with a sealed system, then the F+E tank becomes redundant, and can be removed also.

Reply to
Ron Lowe

"Ron Lowe" wrote

Thanks Ron. My existing tank is a Flowmax thermal store with the header tank built into it so when the existing tank goes so does the header tank.

Are all boilers capable of being part of a sealed system? My existing boiler is a Potterton flamingo which is 18 years old. By being part of a sealed system does than mean the CH pipes and radiators are under pressure because the expansion has no where to go?

Reply to
PC Plod

On Thu, 17 Apr 2008 17:32:42 +0100 someone who may be "PC Plod" wrote this:-

If it is for mains pressure hot water then a thermal store/heat bank is generally a better bet.

Reply to
David Hansen

More bollocks from Dynamo Dave.

Reply to
The Natural Philosopher

On Thu, 17 Apr 2008 18:45:29 +0100 someone who may be The Natural Philosopher wrote this:-

Readers will note that you have not addressed the subject, but have instead made a personal attack. They may draw their own conclusions from that.

Do keep it up.

Reply to
David Hansen

It's scaled up, others in our road have had leaks from the seams so it is time for a change. A direct replacement for my flomax makes a megaflo seem like a bargain.

Anyway back to my question anyone. Also is it a bad idea to seal an 18 year old boiler that was once part of an open vented system. Looking at the boiler manual it would appear that it can be part of a fully pumped sealed system.

Reply to
PC Plod

On Thu, 17 Apr 2008 19:23:44 +0100 someone who may be "PC Plod" wrote this:-

Hard water area presumably. An "unvented" cylinder will also scale up. With a heat bank the only thing to scale up is the heat exchanger, which can be cleaned or replaced while leaving the majority of the system in place.

That is not a function of any particular general design of heat exchanger. All designs can leak at the seams.

Reply to
David Hansen

No, not all boilers can be used in a pressurised system. I don't know about yours.

Your description of a pressurised system is pretty much correct. The primary loop is filled with mains-pressure cold untill it reaches around

1 - 1.5bar. When it heats up, the thermal expansion will raise this to a couple of bar.

There will be an expansion vessel on the circuit somewhere, either in the boiler or mounted externally ( sometimes both ). Otherwise, the water which has a very low compressibility would raise in pressure so much that it would crack open the relief valve, and you'd loose the loop pressure, and the boiler would then shut down for lack of pressure.

If your existing setup has a F+E tank, then the plumber needs to consider this issue. Assuming the boiler cannot be used in a sealed system, then some F+E will need to be provided.

Reply to
Ron Lowe

Not at all. Did this - or plumber did - to a neighbours setup when installing a megaflo.

Works very well.

However I would recommend a water softener on DHW circuits to keep scale down: obviously the primary will be fernoxed.

Shame to bugger a £600 plus tank in a few years due to scaling..

Reply to
The Natural Philosopher

Don't buy a megaflow they can do this:

formatting link

Reply to
Doctor Drivel

Yep. or a high flow combi.

Reply to
Doctor Drivel

Look around. The Flowmaxes did not have enough inhibitor them or have it re-introduced every 4 years.

If it can, it can.

Reply to
Doctor Drivel

The scenario which could cause the guy to say this is if the existing arrangements use a Harcopak "Just add water" (sic). In which case the existing CH circuit has a small F*E tank built into the top of the Harcopak unit, so will need to be added if the harcopak is being traded for a Megaflo.

Reply to
Ed Sirett

No, see FAQ.

My existing

That boioler is certainly unsuitable for a sealed CH system.

By being part of

See FAQ.

Reply to
Ed Sirett

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.