Light Commercial Boiler Reviews

[Ermintrude]

Yeh pump on heating side and use pumps on boilers. If using LLH recommended to fit nrv on returns of boilers. As if using plate u will need to tee both boilers together before plate

 

[tm plumbing]

Yeh pump on heating side and use pumps on boilers. If using LLH recommended to fit nrv on returns of boilers. As if using plate u will need to tee both boilers together before plate

Thanks for that Erm, i suppose I shouldn't need the LLH if I'm using the plate ? as I noticed the Worcester LLH only has 3 zones & I need 4. First time I've used a plate so learning as I go here.

 

[Ermintrude]

Oooh I just thought buy a twin coil or high surface area coil cylinder and pressurise coil and use body as a headder / buffer. Save a fortune and stop those systems from cycling.

Just think a plate on a dirty old rusty system = problems . Once the rust is packed into that plate may aswell buy a new one . Unless is a plate and frame..... Then u just need 4 hours to strip and rebuild plus gaskets.

 

[Ermintrude]

Thanks for that Erm, i suppose I shouldn't need the LLH if I'm using the plate ? as I noticed the Worcester LLH only has 3 zones & I need 4. First time I've used a plate so learning as I go here.

Sorry poorly explained. Both boilers will need to be linked so at the plate u have one flow and one return. To prevent boilers from pushing against each other or bypassing u will need nrv .

 

[tm plumbing]

To be honest I power flushed the pipework on Friday and was surprised as it wasn't as bad as I'd feared, so was intending fitting a boilermag xl before plate, with a strainer.

I'm hoping to keep it as simple as poss with the primary side being where all the work is although I might have to replace the big heating pump for a more efficient one.

Any idea of the best way of wiring 4 zones, the heating pump & the boilers to suit as I don't think the spark will enjoy what I'm after.

ps i was looking at the Horstmann h47xl series 2

 

[tm plumbing]

Sorry poorly explained. Both boilers will need to be linked so at the plate u have one flow and one return. To prevent boilers from pushing against each other or bypassing u will need nrv .

Yeh i was planning to link them, insert hot water zone valve tee then into plate, but yes 2 nrv on return other than that it should be a normal unvented setup on primary's.
im thinking an auto bypass on the flow/return after I've linked the 2 boilers before going into the plate.

 

[Ermintrude]

Why would u need bypass? Plate always open. Or were u going to zone the plate and the unvented?

Zones easy. S/l from timer ( master 7 day) each zone as prog stat in series. Then contacts all s/l back to boiler . Pump controlled by boiler s/l ( assuming single phase)?signal.

Wouldn't boilers last a little longer and wouldn't u feel a bit better running them to a small LLH and then pump off to plate And pump and valve off to cyl?

 

[Ermintrude]

Any one else want to comment? It's a forum not a private 1:1 chat room. Unless anyone wants to shine my 10mm chrome restrictor elbow?

 

[tm plumbing]

Why would u need bypass? Plate always open. Or were u going to zone the plate and the unvented?

Zones easy. S/l from timer ( master 7 day) each zone as prog stat in series. Then contacts all s/l back to boiler . Pump controlled by boiler s/l ( assuming single phase)?signal.

Wouldn't boilers last a little longer and wouldn't u feel a bit better running them to a small LLH and then pump off to plate And pump and valve off to cyl?

I was going to zone the 2 unvented cylinders then leave the existing 3 bigger circuit zone valves in place only picking up they're wiring, you're right no bypass required as plate always open. I don't mind fitting a LLH if it benefits the system I'm just not familiar on how to do it in conjunction with the plate & the Worcester one only has 3 zones, plus where to put pumps on system.

 

[Ermintrude]

Well me being me.....

Yes prevents thermal shock and boilers have good flow through them so hex don't distort.

Make it out if 105mm copper tube or 76mm if your poor .

Just set up plate like a normal zone off plate and two unventeds as two separate aswell . Be more precise and smoother on boilers. Still tee boilers together in to headder

 

[Ermintrude]

Then on other side of plate pump and z/v like the plate is a heat only boiler ( that's what it is if you look at it mechanically !)

 

[tm plumbing]

This was the one I was looking at
http://www.worcester-bosch.co.uk/cache/file/31/cascading-greenstar-regular-gas-boilers.pdf
Still a zone short though
appreciate your advise it's helped me get my head round it a bit more.

 

[tm plumbing]

Headers

I'm going to give these guys a call for a price for the 105mm version.

 

[Ermintrude]

U can get 2m length for £70 ish and reducing tees £45 ?

 

[Ermintrude]

One on first page looked ideal. Two ports for unvented and one for plate?

 

[happyflyer]

Ermi this thing is like system balancing it will run forever.

I see it this way and perhaps you who has had a lot of experience in both Commercial and domestic, you may agree in part with me.

If you are using two boilers on any system it's got to be a LLH
If you are putting a single new boiler on an old system and its flush out do you need a PEX to separate the old crappy system
from the new boiler. My take on it is no you don't.

If you flush the system and put a mag filter on it surely that should do, do boilers fail early in life because the HX fails, I don't know perhaps some of you out there know more and do HX fail early because of a dirty system or just poor flow rate across the HX from day one. I have no doubt if you guys are fitting bypass valves you will never know if the correct flow is going through the boiler ever you have no way of measuring it, you know if its not good when the boiler starts to kettle, unless you are deaf.

If you fit a LLH on a single boiler you can almost be certain the water flow in the boiler side will not drop at all, as long as you fit the correct size pump on the primary side, so the LLH is a plus then, but it means using two pumps and the cost of the header, does the custard want to pay for that, what the cost of a boiler over say 5 years not too much and how long do the new low water content boiler last.

I think if you try and get as much crap out of a system as you can, fit the magic mag-filter the boiler should last 10 years at least as long as you make sure the flow rate is OK, incidentally all manufactures put 2 thermistor on their boilers to try and calculate the min boiler flow rate, it's crude but it is a cheap way of having a bash at it.

What do you think Ermi???

Perfection is good to have I agree, but your are in a crappy old business, who will do the job the cheapest

 

[happyflyer]

This was the one I was looking at
http://www.worcester-bosch.co.uk/cache/file/31/cascading-greenstar-regular-gas-boilers.pdf
Still a zone short though
appreciate your advise it's helped me get my head round it a bit more.

Good Drawing you would expect from WB

 

[stevetheplumber]

been following this without commenting what does a low loss header do that oversized pipework doesnt ?years ago we fitted 4 vaillants in a boiler room replacing a 300000 boiler and just run a 42mm flow and return with a bypass at the end and teed of of that for each circuit ,feed and vent and it worked fine pumps in each boiler and large circuit dual pump set

 

[happyflyer]

been following this without commenting what does a low loss header do that oversized pipework doesnt ?years ago we fitted 4 vaillants in a boiler room replacing a 300000 boiler and just run a 42mm flow and return with a bypass at the end and teed of of that for each circuit ,feed and vent and it worked fine pumps in each boiler and large circuit dual pump set

Just what it says on the label LLH Low Loss Header, one side should not have any pressure influence on the other, maybe your way just did it by default, but to be sure fit a LLH then there is no risk, you know what boiler people are like if they come to site and sniff any way out they can say you should have fitted one, look at the WB drawing if you do it like that they can't snipe you. LLH is recognise as a fix it for two or more boilers, don't forget the NRV on each boiler very important, if one boiler is firing and the other start to get heated up number 2 boiler starting scratching its head wondering where the heat is coming from.

Tony

 

[tm plumbing]

One on first page looked ideal. Two ports for unvented and one for plate?

Getting a quote from them but just want to check what I want of the LLH
at the moment where the old boiler came out, on the flow there is a 2" flanged pump which then feeds into 3 heating zone valves 1 is 2" another 1"1/2 & third 1"1/4, there is also a fourth without zone valve feeding the calorofier. (not now needed)
For this to work properly wouldn't I be better stripping out the 2" iron & existing zone valves then ordering the LLH with 4 1" zones on the secondary side, fit new 1" zone valves to each then a pump for each circuit. Or stick with 2 zones off the LLH 1 for all heating circuits combined & 1 for twining the unventeds.
i know the first option means buying 4 pumps but surely this has to be the most efficient way of doing this otherwise the 3 heating zones will compete if off the existing one large pump with possible flow issues.
need to get this LLH ordered.

 

[Ermintrude]

Agreed with elderly baldy.

 

[tm plumbing]

Just realised doing 4 zones of LLH isn't possible as all heating need to go through plate so 2 it is.

 

[Pipes Plumbing]

Try VA heating for a LLH on 01782 845633.
Used them a fair few times for LLHs made to spec. Do the sizing, give them a drawing and away they go. Good value too!

 

[tm plumbing]

Try VA heating for a LLH on 01782 845633.
Used them a fair few times for LLHs made to spec. Do the sizing, give them a drawing and away they go. Good value too!

Yes thanks I'm waiting on a cost from them, hopefully tomorrow.
I'm also going to strip out the 3 large commercial zone valves on this system & replace them with 3 28mm Honeywell with a separate pump for each leg. Think this will pull better balance from the LLH
A bit more in this than I first thought but if it's worth doing its worth doing right IMO

 

[Ermintrude]

Don't forget balancing valves on returns