Shower pump query..........
- Thread starter JDLDIY
- Start date
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D
Doctor Drivel
To be more specific (and slightly more helpful), try this page:
http://www.heatweb.com/editorials/heatbanks/compare2.htm
and this one:
http://www.heatweb.com/editorials/heatbanks/compare1.htm
http://www.heatweb.com/editorials/heatbanks/compare2.htm
and this one:
http://www.heatweb.com/editorials/heatbanks/compare1.htm
Excellent! Now I can have the extractor fan come on automatically when the shower is turned on. AC version here:
http://uk.farnell.com/jsp/Industria...ATIONAL)/FS-05/displayProduct.jsp?sku=1006768
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Well many thanks to you DD and Softus for the info on heat banks, I'd never heard of them. Never been mentioned by the plumber either, are they not widely fitted/known about?
So what are their disadvantages? Do the pumps make much noise? I guess all I can think of is that you don't have a store of hot water, is there much of a delay in hot water coming through after turning a tap on?
So what are their disadvantages? Do the pumps make much noise? I guess all I can think of is that you don't have a store of hot water, is there much of a delay in hot water coming through after turning a tap on?
D
Doctor Drivel
There are whole estates fitted with them. The average jobbing plumber doesn't have the brains to figure them out. They are simple.
If specified and fitted properly, none.
Quiet Grundfos standard CH pumps.
There a store of hot water. The heat from the stored water is instantly transfered to the incoming mains cold water. Hot water is instant. No lag.
OK, but if your mains fails for any reason you don't have a store of hot water in a tank as with a standard system. That's what I was thinking, am I right? Not really sure this is something which would bother me, just trying to make sure I've thought it all through properly. I certainly like the idea of not having to get them checked every year like you would with an unvented cylinder.
D
Doctor Drivel
You can always have an internal DHW take-ff coil which precludes the plate heat exchanger and DHW pump. Or a hybrid which will have an internal coil to pre-heat the DHW and then a pump and plate heat exchanger after. Or both in parallel with the coil doing the kitchen and basins, so the pump never cuts in and the plate supplying the shower and bath. Cost more though.
Internal coil thermal store:
Explanation:
http://www.gledhill.net/building-products/product-index/pdfs/torrent_how.pdf
http://www.gledhill.net/building-products/bp-index.htm
http://www.mcdonald-engineers.com/products/thermflow.htm
You can also run your CH circuit off the store - highly advisable. Have TRVs on all rads and use a Grundfos Alpha or Wilo Smart auto speed pump. This does away with a nuisance room stat. Have a Magnaclean filter on the CH return to the heat bank.
Firstly, regarding some of the drivel posted by Drivel, see this.
Moving on...
Of the top of my head, the main disadvantages of the thermal store, compared to a gravity fed hot water service, are as follows:
__________________
A. For the coil HEX option:
1. The cylinder is more costly to buy and to replace.
2. Unless you have softened water, the coil will scale up and need periodic descaling.
__________________
B. For the plate HEX option:
1. Heat exchanger and pump have an installation/maintenance/replacement cost.
2. Unless you have softened water, the plate HEX will scale up and need periodic descaling or replacing.
3. You can't shower during a power cut.
Another pitfall that DD has failed to mention is that you must not run the CH system and whole house DHW from the heat store. This is because the CH system must be a closed system and contain chemical corrosion inhibitor that isn't suitable for coming out of hot taps, not an open and constantly replenished with fresh water.
Moving on...
That's grossly misleading. There are pros and cons in any installation. If you don't know what the disadvantages are then you don't understand domestic hot water systems. It would be [more] accurate to say that the advantages, for many people, outweigh the disadvantages.Doctor Drivel said:
Of the top of my head, the main disadvantages of the thermal store, compared to a gravity fed hot water service, are as follows:
__________________
A. For the coil HEX option:
1. The cylinder is more costly to buy and to replace.
2. Unless you have softened water, the coil will scale up and need periodic descaling.
__________________
B. For the plate HEX option:
1. Heat exchanger and pump have an installation/maintenance/replacement cost.
2. Unless you have softened water, the plate HEX will scale up and need periodic descaling or replacing.
3. You can't shower during a power cut.
Another pitfall that DD has failed to mention is that you must not run the CH system and whole house DHW from the heat store. This is because the CH system must be a closed system and contain chemical corrosion inhibitor that isn't suitable for coming out of hot taps, not an open and constantly replenished with fresh water.
Naturally there is some delay, because of the water languishing in the pipework, but not because of the heat exchanger. If you have a simple control system (flow switch and pump on maximum speed) then the temperature will stabilise quickly (compared to a Gledhill control system with feedback control, which takes quite a few seconds to stabilise).
D
Doctor Drivel
You still don't understand power and energy. Laughable!!!!!
Once again for you....If fitted properly they have no disadvantages.
Now for a laugh....
The comparison is against an unvented cylinder. Even against a gravity cylinder the advantages are clearly great. No masses of pipework and the labour putting it in.
The same with any type of water system in hard water areas. Install de-scalers.
Like what? Installation? They come as a unit. Replacement? The stainless plate heat X will last decades. The pump? Minimum 10 years. It is a normal Grundfos Ch pump.
He goes on....
Total tripe. The larger plates resist scale build up as the plates flex. No periodic anything at all.
He continues....
Yep and we get them every week don't we? My last cut was 20 years ago for 2 hours.
What the hell are you on about you amateur. You clearly haven't a clue how thermal stores ad heat bank work. The DHW does not come in contact with CH or stored water.
I guess all I can think of is that you don't have a store of hot water, is there much of a delay in hot water coming through after turning a tap on?
Naturally there is some delay, because of the water languishing in the pipework, but not because of the heat exchanger. If you have a simple control system (flow switch and pump on maximum speed) then the temperature will stabilise quickly (compared to a Gledhill control system with feedback control, which takes quite a few seconds to stabilise).[/quote]
..and not noticeable by the average punter.
Please do not take any notice of this DRIVEL by Softus. Softus in the head.
.
It's plain to everyone (other than you) that it's you who doesn't understand. I don't doubt that you think you understand, but the words suggest that you're incapable of conveying that understanding to anyone.Doctor Drivel said:
That is untrue, and clearly is misleading.
You can make whatever comparison you wish. I stated my comparison to be against a vented/gravity cylinder.
I agree, but I didn't list the advantages, only the disadvantages, so that the OP had balanced information.
Not so - the coil and plate HEX will scale up on the mains side.
That would help, but it is an expense that you didn't mention before.
That's right, and you have to pay for them.
It isn't warranted for decades though. And when it does wear out, it will need to be replaced, which will cost money. I didn't imply that that it's life will be short, or that it will be long; I was merely pointing out that it has a cost. If you're not used to thinking about things in terms of cost and benefit, this might not have occurred to you.
I don't know what you mean by normal, but not all CH pumps last for 10 years. If you're personally providing a 10 year warranty to the OP, then fair enough, but if not then your claim has no substance or merit.
So far this year I've descaled three Gledhill plate heat exchangers. You appear to be saying that it was tripe instead of scale.
I don't think it was tripe, because it had the white and crusty attributes of limescale, rather than the spongy feel and whiffy pong of bovine offal. Perhaps you're right, and it was an accumulation of reticulum that Three Valleys Water are failing to filter out of the water supply. When I do the next one I'll undertake a full spectrographic analysis of the deposits before I douse it in DS-40. Just so that we can be sure.
I'd like to think that it's good that you agree, but your opinion has no value other than in comedy.
You say "does not", I say "must not" - the outcome is the same.
I was making it clear to the OP so that he understands, because an understanding is what he is seeking
That's for the punter to decide, not you. Either the forum provides accurate and balanced information, or it doesn't. Since you don't provide it I really don't see the point of your membership.
Perhaps it's time for you to change your user name again?
D
Doctor Drivel
You still do not understand power and energy. Read the little tutorial I gave you. Remember it!!
In hard water areas scale prevention must be implemented in any water system. That goes without saying.
Using the wider plate heat exchangers gives more plate flex, and they resist scale. They will last decades, being made of stainless steel.
A heat bank comes as a unit. You connect up the pipes and the power - simple!!!! They are cheaper, or no more expensive than unvented cylinders and act with higher pressures.
A normal Grundfos CH pump will give at least 10 years if in the right environment. A DHW pump on a heat bank is on the cooler return and has full flow - ideal. Put a CH pump in normal rad circuit on the hot flow with TRVs that restrict flow and then potential problems. I have come across many CH pumps that are 25 years old and still going.
Once again....the DHW does not come into contact with the CH water!!!!!!!! What world are you in?
Accurate and balance info? You don't know what that means. Also a vented heat bank is failsafe.
Have the heat bank do the rads as well and the boiler then is in a superior hydraulic environment too giving longevity to the boiler. And a simpler cheaper boiler can be used.
No contest a heat bank wins hands down.
.
I predict that you will continue believing and writing this, so any further comment by me is a waste of time.Doctor Drivel said:
And yet, for some reason, the manufacturers feel the need to say it. The cost needs to be budgeted for, unless you have so much money that you don't need to budget.
If the resistance were as effective as you claim, which it isn't, you wouldn't you need to install the scale prevention that you said was essential.
They are not cheaper. They are more expensive.
You seem obsessed with how long it will last. It doesn't matter how long, because whenever it does wear out it will cost more than zero money to replace it.
Not "does not", but "must not".
It means accurate and balanced.
Well whoop-de-do.
Except on installation cost. Oh, and providing a shower in a power cut.
Right then. It's now time for me to click this:
Goodbye, Water Systems, or Drivel, or whomever you next become.
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