Thorn Oil Boiler problems

I have solved the problem of the noise by fitting new Oil pump but i would like to ensure that all the Set up for the burner etc is correct.
Does anyone out there have a Tech Manual that would contain Exploded views and settings for the following??? and if so could supply pics or Photocopies??

Thorn Boiler Model ODY-3 Ser # B4/7/11,96A. Fitted with Motor/blower assy :- Selector/Selectos D42/K. 1073/2022332. (new pump by Suntec)
Rated at 3.78 ltr Per hr. Grade 35.
I would be realy greatfull for any help on this as i like to know that the job is done correctly. (judging by the flame color and \\\"Ball\\\" its going weel but is it at max efficiency.
Chris.

Drawings wont help here. You need a combustion analyser to set it up correctly.

Thanks OILMAN,
that's sound advice but i feel that there must be something to enable the correct assembly of the projecting oil spray assembly within the blower passage and the correct location / spacing of the electrodes etc prior to flame analyzing?
Some one has to put the thing together in the first place or on re-assembly?
My friend is ex Gas Co eng emergency call out so knows about flame but has no prior about the assembly of unit.
I have just fitted a hour counter to see how long the boiler is actually on for over its thermostat time.
Its up to a water temp of 160 degrees in approx 15 mins so is quite quick to warm up 12 rads (some doubles).

Fair comment, but the nozzle/swirl plate distance is correct with a minimum reading of CO, and the electrodes are set to be midway between the nozzle and the swirl plate. Hence the benefit of an analyser.

There's really is no scope for changing anything in my opinion.
I fit a new nozzle every year. I leave the air flow set as it as always been (central). I have verified the nozzle positon as being 6mm back from the 'flame ring' and thats about it. Oh I did use a pressure gauge before and after I fitted a new pump to check the oil pressure. I think it was 19 lbs per sq. in when it should have been 100 lbs per sq. in. hence new pump
There are 3 ratings for this boiler 60.....75....90 so there are some slight differences. Do you know which you have?
The fuel can be gas oil or kerosene, which are you using?

There is anadjustment for the nozzle/swirl plate distance. If you fit a new nozzle (this is not necessary every year anyway) then the combustion should be checked. All nozzles are not the same, as the E series have a 5% tolerance and the standard ones have 15% tolerance. ie same effect as 15 psi in a nominal setting of 100 psi.

I agree there is an adjustment catered for by the means of a nut which is secured with a locking nut and it is not disturbed when the nozzle assembly is removed. Agreed not all nozzles are the same but I have always used the same monarch 80 degrees AR.
Regarding the electrodes, the end of the electrodes are in line with the front end of the nozzle, but due to the shape it does mean the spark is back about 7mm. Gap between electrodes should be 3/32 in. plus or minus 1/32.

Thank you Oilman and Mandate. all good info.
Just what i needed.
I can confirm that the nozzle is 80 degree @3.78 litres per hour rated.
I did not put a pressure gauge on as i could see from the spray and the pump internals that there was low pressure due to wear and tear. (used to oil pumps on American V8's.) Hindsight just kicked in.
I seem to have struck lucky with the reassembly as i have the swirl plate clamp slid all the way up to the end of the nozzle tube which gives a nozzle tip to swirl edge of approx 6mm and the ends of the spark rods are level with the nozzle tip with a gap of approx 1/4".
I use homeglow 35 gas oil but when the problems started i did have the oil co deliver a lower quantity of oil and added some kerosene to thin the lot out which helped it burn better??
I have a few spares which is handy. I make a point of doing that due to previous problems with cars. I have a spare spray assembly which has a cast swirl plate which does not seem to work as well as the pressed steel vaned version. I have not yet used a new nozzle as i keep one spare which i dissamble and clean out with fuse wire and keep in its little plastic box as a just in case item.
I do clean out the heat box each year of all that shale.
At the moment it is thermostat timed heat controled for 8 hours a day and seems to fire up for only half of that time because of its internal stat and room stat combo. The rest of the day it switches to freeze/min temp setting to protect the pipes etc.
uses 2500 litres of oil a year give or take a few but boy the price has gone up 100%
I have 3 differant models of electronic control units as back up and a spare motor/blower assembly.
Knowing my luck i have enough bits to see me out but it will go and pop a rust hole at the lowest point in the boiler case and i will end up having to renew.
You mention the adjustment nuts at the top of the assembly. Thats one of the places i would like to know the initial trial setting for the ammount of protrusion into the boiler heat box.? That must make a differance to the performance once you get to the analyzer stage.
Just in case it helps you guys. I picked up a sheet of heat/flame proof insulation material 1000 x 600 and approx 10mm thick when at the trade depot.
Its white and brittle, cuts with a stanley knife.
I cut two pieces, one smaller than the other and these fitted into the front cover. I put two layers of cooking foil over the face of the larger one which was closest to flame.
They are held in place by the cover when bolted into place by the 4 bolts.
You can put your hand on the cover whilst peering in to the view hole without losing any skin.
Hope this helps in some small way to repay your help.
Happy Days,
Chris.

You shouldn't need to make up special recipies of oil. The difference is accomodated by adjusting the pressure.

I wouldnt bother cleaning a nozzle. They are so accurate you can only make them worse, NEVER better. However using diesel does make them last a VERY long time.

In most boilers, you can't see the flame, and even when you can, it's such a big adjustment before you can see a change, an analyser is the only way to do it, unless you opt for using a smoke test, but then you can't see the CO figure.

Hi Chris; Your nozzle rated at 3.78 lit/hr seems high to me. This is the equivilent of 1 US gallon.
The specified nozzle is a monarch 80 deg AR rated at 0.65 for the 60btu/hr or 0.75 for the 75btu/hr or 0.85 for the 90 btu/hr. The 0.85 is the delivery rate in US galls/hr at 100 lbs/sq in
If your nozzle is rated at 1 US gal as against 0.85 then I'm thinking you have a 90 btu/h boiler. If you have the 90 rating, the pump pressure should be 120 lbs /sq in for kerosene or 100 lbs/sq in for gas oil.
I think you need a pressure gauge and perhaps try the 0.85 monarch nozzle.

Oops, I omitted in my post to say the nozzle size would be smaller, as well as the pressure being higher. This accomodates the different calorific value of the fuel, and gives good atomising to reduce sooting and CO to acceptable levels. The nozzle would be about 75% of the kerosene nozzle, with a suitable pressure adjustment.

Chris; A bit more information I had overlooked.
There was a modification to the burner around 1973.
Prior to the mod the 'flame ring' was clamped to the nozzle assembly so you checked/adjusted the 6mm (face of nozzle to flame ring) before fitting the assembly. After fitting the top end adjustment was used to line up the 'flame ring' to the ' draught tube'.
After the modification the 'flame ring' was welded to the 'draught tube'. The clamp was removed so the nozzle assy was now a sliding fit in the 'flame ring'. This means the top end adjustment now controls the 6mm dim. after fitting the nozzle assy.
Regarding the electrode gap of 3/32, I fitted a new transformer and found it was not powerful enough to create a spark across 3/32 so had to reduce the gap.
Out of interest does your new pump have a solinoid or not? and do you know make model of Control box.
If you change from pump without solinoid to pump with solinoid the wiring is slightly different, (only nobody told me at the time)

I usually set the contact separation as 3mm
30,000v/mm is the breakdown of air ie voltage required per mm of gap to make a spark. This is also the setting on Rieillo burners.
John_D

MANDATE said:

Chris; A bit more information I had overlooked.
There was a modification to the burner around 1973.
Prior to the mod the 'flame ring' was clamped to the nozzle assembly so you checked/adjusted the 6mm (face of nozzle to flame ring) before fitting the assembly. After fitting the top end adjustment was used to line up the 'flame ring' to the ' draught tube'.
After the modification the 'flame ring' was welded to the 'draught tube'. The clamp was removed so the nozzle assy was now a sliding fit in the 'flame ring'. This means the top end adjustment now controls the 6mm dim. after fitting the nozzle assy.
Regarding the electrode gap of 3/32, I fitted a new transformer and found it was not powerful enough to create a spark across 3/32 so had to reduce the gap.
Out of interest does your new pump have a solinoid or not? and do you know make model of Control box.
If you change from pump without solinoid to pump with solinoid the wiring is slightly different, (only nobody told me at the time)

Click to expand...

Hello to all in the past. I and the boiler are still going strong. Could be some sort of a record?
Lots of trouble with old emails and Health hence long time out but I have managed to get back in to forum.
Since the last posts I have discovered a product called 'Vermiculite' works a dream in the front plate of boiler especially as the sight glass and its tube have gone leaving a hole. Still got the pin hole weeping water but this summer I will get it brazed.
I have replaced the fan motor and just installed a new pump but only because of what could be a problem?
Just had a new 1000 ltr oil delivery and the boiler does not like it. Boiler was fine until this. All my filters are cleaned prior to tank switching on. Could it be that my oil man has given me the wrong fuel? How do I tell? I am going to dig out my oil gauge kit and have ordered two new nozzles and so will have to see what happens. Got some oil filled radiators going to help make up for the % loss in thermal efficiency .

Im surprised it has any baffles left... what is FGT. ??