Advice: new CH system

[Doctor Drivel]

He has a high pressure cylinder working low pressure. best he fits an accumulator to get the mains water pressure/flow up to scratch and convert the cylinder into a heat bank.

[Andy Hall]

Becomes rather pointless then, because the cylinder would need to be the same size as a HW cylinder, and the temperature of the HW produced less than 60 degrees.

????

Why would one seal it? One of the main points is not to need to do that.

Mmmm.........

Hardly a common occurence though, is it?

[Andy Hall]

Still in development. Tuit shortage.

The radiator control and data logging is effective, the main part is coming up with a suitable front end interface.

[Doctor Drivel]

If you think so. Please eff off as you are stupid.

[Doctor Drivel]

Using a double pass Danfoss plate heat exchanger 50-55C can be obtained at the taps.

Another option. All he system, boiler CH pipes and cylinder are sealed. It virtually eliminates any sludging.

Easy to do Matt.

[Andy Hall]

It is, but rather a pointless one. If the whole thing is going to be sealed, then one might just as well have the pressurised HW cyulinder in the first place.

I'm sure. It wasn't you was it?

[Doctor Drivel]

Not at all. A thermal store is a great neutral point and buffer for CH and the boiler. Worth having for that alone. Also TRVs on all rads with all zones going back to the store (the neutral point) is an advantage. All using the same water, no heat exchangers to reduce efficiency, with little chance of sludge build up is an advantage. A DHW only unvented cylinder does not give you what a pressurised thermal store/heat bank does in any way. Also a pressured thermal store using a plate heat exchanger can be DIYed, no Building Control notification and no annual service. I would have two pressure relief valves just to be sure - the boiler usually provides one anyway.

In Germany a heat buffer is becoming pretty standard on many installations, just a small cylinder in the CH line, the thermal store/heat bank does this for free, it also does boiler buffering for free too...and it goes high flow instant DHW.

Here is one German system. They use a pressurised cylinder with fresh water in the boiler and through the heating circuit. Look at the system as primary water and add an external plate heat exchanger for DHW take off and it is all there for the UK market.

"Compact systems with just one tank [thermal store] that also acts as buffer storage for the boiler dominate the German market. In conjunction with wood-burning boilers there remain no alternatives since such a buffer volume is urgently needed for their use. However, combination tanks with integrated gas or oil burners use a large storage tank to replace the boiler and its tank for heating domestic water [integrated thermal stores]."

The Germans are way ahead of us.

I don't live in America. Has yours gone kaboom? Understandable.

[Dave Plowman (News)]

More belief in adspeak. Please confine your comments to things you know about. Looking forward to blank pages.

[Doctor Drivel]

Please eff off, as you are an idiot.

[Ed Sirett]

I think you might do well to read the BoilerChoice FAQ.

I have no strong preference for or against unvented cylinders. They are not liked on this newsgroup because the regulations require the use of a qualified installer and a notification to building control (the latter is not relevant because installing a vented cylinder is also a notifiable activity).

However, I acknowledge my bias as I do hold a G3 card (the unvented HW storage qualification).

A properly installed mains pressure HW system (whether unvented, heat bank or thermal store) will make the use of a pump both illegal and unnecessary. Not all properties are suitable for mains pressure installations.

HTH

[Doctor Drivel]

It is about 20 years out of date.

You forgot the annual service charge. That precludes them full stop.

They are if an accumulator is fitted. See my post on how to make one up.

[Doctor Drivel]

Another approach is to have a Rinnai multi-point high flow water heater (which can also be fitted outside) and a small CH boiler. No space taken up and high flow at mains pressure. Cost is about the same, or maybe cheaper than a boiler/unvented cylinder/heat bank. Both can go in the loft as well. The downside is the Rinnai may need a service as does the unvented cylinder. One big plus is that you never run out of hot water and can run multi-jet Tower Showers from it and "never" run out of hot water. No standing heat losses either.

[Andy Wade]

A familiar state of affairs.

Announcements awaited with interest...