Some info required for radiators that aren't performing so well!

[hary_j]

Hi Gents,

I'm currently doing a Job at a small warehouse where i've been fitting a Basin and toilet, the owner of the premises is a close friend of mines and has just recently taken over the premises.

The problem i've come across is, the radiators in this place are not warming up so well, practically luke warm!..

It is a large system comprimising of 14 Double convector Double panel radiators (Approx 700x1200) in size.

The system is no more then 2yrs old because we have some form of paper work, just no installer details.

There is a Vaillant Ecotec plus 937 installed, seen as there was 2 existing toilets and 1 kitchen.. Now i''ve added another basin and toilet.

The Hotwater side of the system is completely fine, just the heating.

So far i've gathered some info from Vaillant technical support (pretty poor technical staff), and have purchase a "VR40" which has allowed me to fit an External pump on the heating circuit.. I have fitted this and have not seen any differences what so ever!

So yestrday (Saturday afternoon) i have placed an order for a 23 litre expansion vessel and will be fitting this as obviously the standard vessel that is fitted inside the boiler cannot cope!

Will fitting this vessel on the Return side of the Heating circuit be beneficial??

I would be grateful if anyone can tell me, if what i'm about to carry out is the next best thing to do??

Thanks guys!

 

[ecowarm]

check the water in the system, it could be sludged up

 

[shorticus]

What makes you think that there's a problem with the expansion vessel?

 

[hary_j]

Ecowarm - The water in the system is very clean, it can be deemed as drinking water from what i've seen.

Shorticus - Im adding another vessel because there is only soo much a the vessel in a 937 combi can cope with, True or not, please fill me in ??

 

[ecowarm]

A large system may need a larger expansion vessel than the one in the boiler

 

[hary_j]

That's right mate, seen as it is large, can what i've suggested solve the issue?

 

[ecowarm]

what size pump have you added?

 

[shorticus]

just checked the manual, the boiler's got a 10l expansion vesel that's good for a 100l system, do you think that the system's larger than that?

 

[hary_j]

Definitely more then a 100litre system mate, cos the flow & return pipe lines from boiler to the last radiator is atleast 23metres from the top of my mind

 

[hary_j]

what size pump have you added?

6Meter head

 

[ecowarm]

15/60?

 

[shorticus]

what about the temperature of the flow and return?

 

[shorticus]

Definitely more then a 100litre system mate, cos the flow & return pipe lines from boiler to the last radiator is atleast 23metres from the top of my mind

just out of curiosity, has the prv discharged?

 

[PuraTherm]

The size of the expansion vessel isn't the reason it isn't heating the space. The problem is that the boiler is spec'd out at 28kW for CH. Thats a load for that boiler in a domestic app let alone a wharehouse.

 

[hary_j]

15/60?

Unfortunately not, it's a Ideal one

 

[hary_j]

what about the temperature of the flow and return?

I've not got around to this yet, the flow warms up OK not the best.

 

[shorticus]

The size of the expansion vessel isn't the reason it isn't heating the space. The problem is that the boiler is spec'd out at 28kW for CH. Thats a load for that boiler in a domestic app let alone a wharehouse.

I was pondering that too, those rads have got to be say 2kw each + pipe loss etc etc

 

[hary_j]

just out of curiosity, has the prv discharged?

I havent seen any water triccle out but it does tend to loose little pressure every few days, with no signs of leak on pipe work, so assuming it is the PRV

 

[shorticus]

one other thing to have a quick check on is the internal auto by-pass, could possibly have a bit of debris on the seat

 

[hary_j]

The size of the expansion vessel isn't the reason it isn't heating the space. The problem is that the boiler is spec'd out at 28kW for CH. Thats a load for that boiler in a domestic app let alone a wharehouse.

That's the 1st thing that came to my mind, but seen as it is a big job and quiet pricey to replace, maybe some essential add-ons may help! :-S

 

[shorticus]

I havent seen any water triccle out but it does tend to loose little pressure every few days, with no signs of leak on pipe work, so assuming it is the PRV

then you're probably right about needing extra space for expansion, not sure it'll cure the heating issue though

 

[hary_j]

one other thing to have a quick check on is the internal auto by-pass, could possibly have a bit of debris on the seat

Could give it a go, but doubt very much as it doesnt look like a very old installation with minimal use!

 

[shorticus]

Could give it a go, but doubt very much as it doesnt look like a very old installation with minimal use!

worth a look just to eliminate it, someone on here last week had a bypass problem so it can occur from time to time.
Make sure you let us know how you get on Hary-j, good luck with it mate

 

[hary_j]

So what you reccan gents??, time for a replacement to a vaillant ecotec 46kw or 65kw??

Really don't wanna have to tell my mate this :-(, so if i can cure it more better!

 

[ecowarm]

looks like a shortfall , 28kw output on boiler and a load of 35kw on rads

 

[hary_j]

yep unfortunately it does. Big shortfall

 

[ecowarm]

dont replace the boiler just add a small system boiler to back it up

 

[hary_j]

Problem is where it is located, space it very very minimal as it goes..

 

[SafeGasInstall]

Has any one ask if is been pipe sized correctly , not that will make big diference as is only 28 kw! I fit 40kw regular boiler on uhwss and about 20 large rads in large house ! Quick and easy heat up and customer well happy in this cold days we having now!

 

[hary_j]

luckily all the pipe work is visible and is in 22mm from boiler, with 15mm tail off's to the rads!

 

[hary_j]

Re: Some info required for radiators that aren't performing so well! "UPDATE"

Thanks for your posts fella's!...

We've come to a solution and decided that the boiler will now be removed and replaced for a "Vaillant ECO TEC 65kw system boiler".. The boiler will be used as Heat only and will have the secondary pump (Already installed) help maintain the flow rate around the Rads! as well as the new boilers pump!

As for the Hot water i will be installing one of them latest stubby instantaneous water heaters.

Before i get blasted about Gas safe!, lol!

Please note - i am not Gas safe/Corgi registered. All my GAS work is carried out with supervision from a pal who is Gas safe and will issue me a certificate on completion..

 

[ecowarm]

You have approx. 35kw of rads why are you going for a 65kw boiler?

 

[hary_j]

35kw is what it rounded upto 1st with my figures, i measured up the rads properly this time and they are infact 700x1400's DCDP, they are 200mm wider and 100mm more in height, and also adding on for the pipe run (approx 32metres).

Each rads output is 8274 BTU = 2.42 KW
x by 15 rads + say another 3kw for pipe runs = 39.3KW

Also in a years time there is possibility that there may be extra individual rooms built, so allowing for them too..

So there's no point in stretching it again, cos there almost 40kw there already and you only got another 6kw to play with..

so thats why i had the 65kw in mind..