Ventilation on a Warm Air heater & circulator

[Simonbeasley1]

Started to install an ensuite for a client. I noticed a lot of vents on internal doors ceilings/walls etc and thought Hot AIR. I had a look in the cupboard upderstairs and found a

Johnson & Starley HI-SPEC J25 WARM AIR HEATER with circulator.

The door was just full of vents top and bottom.

I had a look on the outside of the house and i could not see any external vents apart from one of those that sit in a pain of glass and rotates with a cord to open & close. The door between this external vent and boiler has a 6" in the bottom corner.

I would have thought it would need to be vented top & bottom from an external wall. Any walls in between to then have 50% bigger vents top and bottom again.

Shoul this have an external vents???

http://www.johnsonandstarley.co.uk/downloads/ZZ0753.pdf

regards

Simon
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[Biggles..]

these were normally vented to outside air in the cupboard they were sited in,usually hard to see when hidden behind the unit,ducting and everything else.

obviously if the circulator vent in the window is the only one theres a problem.

 

[simond]

This particular HiSpec installation (from your description) appears to need compartment ventilation plus combustion ventilation. The high and low vents in the compartment are there for this purpose.

The combustion air ventilation thereafter would not normally need to comprise hi and low vents.

The door vent apertures are simple to calculate or J&S give them to you; but if the external vent is closable that is a no no.

Be aware that some HiSpecs have combustion air derived from the return air duct, this is a favourite cause of people wrongly having their WAU cut off, BG staff seem particularly prone on making this mistake.

 

[Simonbeasley1]

thank you for your responses. I think it should have an external vent or use the loft providing sufficeint venting through vent tiles and sofit venting.

Not back their till next week so will spend a little more time on it. I just cant see where it is getting the air for combustion - if it is removing air from a room then it has to be replenished.

Will get back to you next week with my findings.

regards

Simon

p.s. just don't want the client falling into a deep sleep and not paying me for my time on the ensuite.

 

[Paul Barker]

Yes look for a 4" round style vent in the landing ceiling and an "extra flu" in the loft. That's a late way councils deal with the fact they weren't provided with combustion air.

bigger problem is the quite likely eventuality the heat exchanger is split/cracked combining combustion air with warmed air and sending it into every room. councils were geting new heate exchangers for free from J&S if it happened within 10 years.

There seem to be some condensing room sealed ones apearing saw one yesterday Warm Front put in. Has a tray under the flu which collects drips and runs in 3/4" unlagged externally to the pavement. Quality! Actually wish I'd taken a picture, may get a chance to go back next week.

 

[simond]

The condensing units are most probably G61s made by Lennox USA. 94% efficient.

We have recently started specifying them, they're more expensive than J&S but build quality and efficiency is superior.