weird system

[Guildfordboiler]

Hi All

Went to price for a new boiler and the system was a little bit strange never seen it done this way before in 13 yrsin the job

Kingfisher cf180btu in utility room

fully pumped 35mm flow & return think was a pumped return
the F&R went from the boiler low level there was a big myson pump se 150 then there was a branch off in 15 for a rad in the kitchen then off to the floor above where it branches off for the rads i lifted a loose board up near the airing cupboard and could see the feed to the coil just comes off the 35mm the open vent comes off the flow to the coil and feed from f&e tank comes off the return like on a gravity circuit

When the HW is calling the pump doesnt run only when heating is calling does it kick in

the lady said when hw is on some of the rads upstairs get hot which im not supprised

Also 180000 btu seems way to much for the size of the system its only a 4 bedroom house with 17 radiators I didnt measure them as they all had covers over them which the screws had been panted over!! but even if I was to allow 2 kw per rad =34kw 180000but is 52.75 kw!!

Any thoughts guys??

 

[lame plumber]

dont know the boiler but is it range rated to its lowest setting what ever that is, just looked it up and it isnt so bit oversized, the input is 72.3kw!!! small hotel size really, anything you put in will save money

 

[doitmyself]

Use Whole House Boiler Size Calculator to find out what size boiler is really required.

 

[Guildfordboiler]

Yea I dont want to spend hours working all that out as might not even get the job
but 17 rads some small some big thats why if you allow 2kw a rad you be somewhere near there

I am thinking of fitting a 40 cdi there which will be more than powerful enough to heat the house

any thought on the way it has been piped up??

 

[lame plumber]

lots but get yourself gsr proven and we will tell more

 

[happyflyer]

If you tell me how old the house is, what the external and internal walls are, what the total floor area is, I will tell you how much heat it requires per M/2 plus or minus 15%, that will get you started, BTW where in the Country and exposure, is the roof space insulated and how thin, single or double glazed. Adding the rads size up won't give you the heat loss for the building. A Fearns Mear calculator will tell all you need to know, I think they still make them ???


http://www.mathsinstruments.me.uk/page61.html

 

[Howsie]

They do still sell Mears calculators. Surely it would be better of he worked it out himself?

 

[snowhead]

Probably done by a Commercial heating engineer, with access to free 35mm pipe..and possibly a free boiler.

It's basically a gravity H/W and pumped C/H system, maybe a little over specc'd.

Questions for the Occupant, Does the house get warm enough, and how much is the gas bill.

 

[happyflyer]

Surely it would be better of he worked it out himself?

I could not agree more, but if you don't know how to work it out the FM will get you there

 

[happyflyer]

Probably done by a Commercial heating engineer, with access to free 35mm pipe..and possibly a free boiler.

It's basically a gravity H/W and pumped C/H system, maybe a little over specc'd.

Questions for the Occupant, Does the house get warm enough, and how much is the gas bill.

The pipe size of 35 mm is spot on for the 50 Kw boiler , it gives a flow rate of 1.5 m/s and a PD of 500 pa/mtre/run, these two are well within standard design criteria, we only have half a story, when you know how big or small the house is that's when all will be reveal , 17 radiators is a lot of rads, hope he comes back with the whole picture.

Like you said I wouldn't like to be paying the gas bills if that boiler is the right size.

 

[Guildfordboiler]

Probably done by a Commercial heating engineer, with access to free 35mm pipe..and possibly a free boiler.

It's basically a gravity H/W and pumped C/H system, maybe a little over specc'd.

Questions for the Occupant, Does the house get warm enough, and how much is the gas bill.

Right but there are only 2 pipes off the boiler all the gravity Hw systems ive seen had a separate CH & HW circuit this only has 1 the F&R branches off the 35mm pipes for the coil that also feed the rads

The house is a vey old property and has no double glazing and no cavity walls but I asked if the rads heat the house in the winter and she said yes. So no need to do a house calculation just add the kw to heat the existing rads and allowing 2kw per rad like said before is 35 KW

She said her gas bill is a lot!!!

 

[lame plumber]

like any job, forget whats there and start fm scratch to get it right to save them money and keep them warm.

 

[Guildfordboiler]

from experience i know by counting the number of rads in a house and allowing 1.5 kw a rad you are not far off done one a few months back measured all the rads worked out the exact kw needed and was nearly bang the 1.5 kw per rad calculation

dont get me wrong if i get the job i will spend the time and do a proper measure up and calculate it but ive spent hours before working this stuff out only not to get the job so ill price it for a 40kw as i know it wont need anything bigger and if i get the job ill do the exact calculation and might even get away using a smaller boiler

it was the way its piped up that i was a bit curious about as never seen it done this way before

 

[Howsie]

Guessing is for amateurs. Whole house calc is the way to go.

 

[happyflyer]

Guessing is for amateurs. Whole house calc is the way to go.

Howsie,

The only way to go as you say, I'm out of here, I can't give any more advice, I think this house is the one in the film Psycho, hence the weird system. :evil2: