AR or just NCS?

[n2o]

I have encountered a fairly recent (approx. 3 years) gas shop Magiglo DFE gas fire installation. The brick flue has been lined with 5” S/S, but the MI states “16 Elite Thermobox pack incorporating Trim Switch control should not be installed on a 5 (125mm) flue system due to increased switch temperatures caused by reduced flue flow” and the minimum dimension is 55mm. BTW the 8mm copper gas supply pipe is wrapped but not sleeved through the external cavity wall into the fireplace opening.

The nominal maximum heat input is 6.9 kW (gross) so there is no permanent airvent.

Should this be classed as NCS even though it hasn’t been installed to comply with the Manufacturers Instructions or is it serious enough to be classed as AR?

I would be obliged if anyone can shed some light on this (for me) grey area.

 

[kirkgas]

i don't know this fire, so i say check MI's to confirm about ventilation, most (ie 99%) say 100cm2 free air vent required due to their design, don't get too caught up in Heat Input being under 7kw and not needing it as it is a DFE i think it will need the 100cm2 so on that point i would be concerned with its use before i even started to look at the rest of it

 

[lightning]

i thought all dfe fires need 100cm2 ventilation period,unless mi state other wise

 

[Gasguru]

The MI's for this fire say no vent required unless other extractors are present.

As for the undersized flue the risk is that the switch block will overheat and fail. Probably only NCS but you need to refer to the manufacturer since the reason for the switches is to enable infirm customers to turn the fire on/off that they won't be able to do if its melted.

 

[n2o]

Thanks for the replies.

The MI states “For models with heat inputs not exceeding 6.9kW, normal adventitious ventilation is usually sufficient to satisfy the ventilation requirements of these appliances. In GB reference should be made to BS 5871 Part 3, which makes clear the conditions that must be met to demonstrate that sufficient ventilation is available”.

I have HTR1 but I prefer not to get involved with gas fires, especially if I haven’t installed it, but I have got roped into this because they and their extended family are good customers.

They are keen to get the gas shop back to correct the installation faults, but I am unsure whether non compliance with the Manufacturers Instructions should be classed as NCS or AR.

The other worrying things is, as stated in the MI that 5” (125mm) flue system should not have been used, this would mean that the minimum throat dimension should be 100mm

To be safe for the meantime the fire has been turned off and labelled.

Personally, I would rather class it as AR so that it will left turned off until the gas shop have put it right and I don’t need to be concerned about ventilation, etc., but if CORGI get involved would they back me up or will they accuse me of over reacting.

BTW I have just bought a copy of The Gas Industry Unsafe Situations Procedure 4th edition, but I can’t say this has been particularly helpful in this case.

 

[ChrisR]

If the MI say

should not be installed on a 5" (125mm) flue system

An someone installed it on a 5" (125mm) flue system

Then it's AR certainly, just because of the switch box.

If the switch box had actually melted it would be ID and RIDDOR.

Unsleeved pipe is only NCS there.

 

[Gasguru]

The GIUSP never is much use in situations such as yours. Cover yourself, class it as AR, label up and refer them to Corgi. Even if you speak to the manufacturere it's often down to the individual you talk to regarding the risk category.

Many fireplace shops botch the installation...I suspect many do not employ full time rgi's but just get a sign off. Don't worry I AR/ID nearly all fires I come across, a tiny pe4rcentage are installed correctly and in good condition.

Don't worry about Corgi; upgrading the category is playing safe so you should not be criticised and who gives a **** what they say...they are of no importance anyway.

 

[ChrisR]

It's COrgi who invented and decide the IUSP categories, so you could just ring them. They're friendly to rgi's!

 

[n2o]

Thank you everyone that posted. This has been far more helpful than any discussions with CORGI would have been, I am sure.

I will complete the AR procedure and the customer can contact CORGI if they don’t get a satisfactory result from the original installer.

 

[n2o]

My customers have received a reply from the gas shop and they are prepared to change the Trim switch to a remote control, but this still leaves the minimum dimension at the throat of 55mm.

I have explained that this would mean the installation will still not be compliant, but they are not keen about having it altered because of the mess it would cause.

Can one flue fault like this be classed as NCS if there are no signs of splillage?

All views will be eagerly read with thanks.

 

[Gasguru]

Presumerably you only have a dimension of 55mm due to the lintle sitting back too far into the opening.

The throat "design" of the fireplace is intended to accelerate the combustion products into the flue. I assumed the 110±10mm throat dimension has been refined over the years to offer the best performance ie to act as a "nozzle" but not too narrow to be liable to blockage by flue lining debris and birds.

Since the flue now has a 125mm liner (with suitable annular seal) and an approved terminal there is now little chance of throat blockage.

What cross sectional area is the throat? The standards quote a minimum area of 240 cm² however, a 125mm diameter liner is only 123cm², hopefully it is at least this area.

I would say that providing the terminal complies with the minimum distance from the roof etc and there are no other flueing/ventillation faults the reduced throat is just NCS. However, despite an ODS on the fire (that we know are not infallible) I would always recommend a carbon monoxide alarm installation.

 

[n2o]

Apparently, the gas shop returned yesterday to correct all the installation faults and the customer seems very happy.

This is down to you lads and your helpful comments. What a team and what a result!

Thank you.