Grant Module 50-90 starting issue.

Cass

This has probably been asked but in a quick search i found some answers but not an exact one so bear with me.


In the lead up to the winter/Christmas period i've been slowly filling the tank with drums as i'm sure many have had to do. My local supplier will not deliver on less than 250 litres and as i'm on disability that is simply not an option. I had some issues over the last few weeks when i started the heating from a quick reset to having to blow out the lines for fear of crud in it. Basically i have done the following:

• Changed the pump
• Blew out the lines
• Checked and cleaned (although not needed) the filter
• Changed the valve on the fuel line in/over the the burner unit
• Changed the spray nozzle.
• Checked and freed up the fan on the right side that was partially seized.

The system has stopped three times and one was due to running out of fuel. I last replaced the pump as when i checked the bleed valve the fuel was barely dribbling out. When i replaced the pump the fuel flies out so i thought all was grand. However i cannot get the system to fire up. It has got going and stayed running but stopped a few hours later and now i cannot get it going again.

It starts the start up sequence, but stops just as the burner should "kick in". My first thought was the photocell, but as it has never caused a problem i thought better. Still i changed it for a new one and still nothing. I have numerous parts, all new, and the only thing i've yet to replace is the control box, solenoid or capacitor. Would any of these have an affect on it starting up or should i turn my attention back to one of the others.


I'm not a fitter so all this is on my own bat and all has been done over the last two days (since Friday evening). I'm going to call the guy i normally use tomorrow, but it's a very rural area and it's usually a few days before he gets to me (only one in the area). The issue is my Mother is disabled and the house is freezing from no heating the last few days. She is wrapped up in blankets/jackets with electric heaters in the rooms to keep the chill out but they are a poor substitute.


Any advice gratefully accepted/received. Thanks.

shane0007

If you have a control box, swap it over & see. It is not a testable component anyhow.
What burner is it, G series or RDB?

Cass

I have a control box, and it's the RDB model.

Wearb

Did you change the plastic coupler when you changed the pump? Why was the fan stuck? Did it seem stuck when you tried to move it? Was the pump attached to the burner at the time?

To me it seems it might be a fuel delivery problem and I would like to see the start-up sequence with a Pressure and vacuum gauge attached. It could be some other problem, but you have to start with basics. It is too expensive to keep buying and replacing parts. In your case you have already spent nearly half the price of a new burner. I would advise waiting for your technician.

shane0007

Cass wrote: »

I have a control box, and it's the RDB model.

I would change it to try as if you are days from a technician calling & need the heat on, it maybe worth it.

As Wearb says correctly, there could be other issues, but difficult to determine if you have no test equipment.

Fan stiff could have been old pump. Fuel flowing strong under pump pressure would signify sufficient fuel.

Capacitor is not the issue. Even if you get it going, still call your technician to set it up correctly.

DGOBS

Reset the burner, let it run to lockout, once it has, remove it from the boiler and see is the blast tube (front piece of the burner) wet with fuel. Come back to us with the answer, it will start us down the right path.

Your burner sequence should be, from start of motor 12 seconds then fires up, or after 5 more seconds lock out (in simple terms)

Cass

Wearb wrote: »

Did you change the plastic coupler when you changed the pump? Why was the fan stuck? Did it seem stuck when you tried to move it? Was the pump attached to the burner at the time?

I did not change the coupler. I kept the original one in the unit. When at the unit a couple of weeks ago fuel got spilled and i think i removed any lubricant on/around the fan and when i started the sequence i could tell by the sound that the fan was not turning. i turned it off, removed the casing, turned it by hand, greased/oiled it, and it's worked perfectly since.

To me it seems it might be a fuel delivery problem and I would like to see the start-up sequence with a Pressure and vacuum gauge attached.

Don't have those tools, but it's not a fuel delivery problem. The fuel is getting to where it should, and while visual measurements are not anything to go by the pressure is 20 times that of what it was before i changed the pump. When i bleed the system after the shut off the old pump would barely have the fuel dribbling out of the bleed valve/nozzle. now it shoots out like it did many months ago before the problem arose.

Also before i changed the pump, and while the fuel was only trickling the burner would eventually get up and start, and keep going. It just got harder and harder to start hence the reason i changed the pump.

It could be some other problem, but you have to start with basics. It is too expensive to keep buying and replacing parts. In your case you have already spent nearly half the price of a new burner. I would advise waiting for your technician.

I've spent nothing on parts hence the reason i have so many and am changing them myself. As for waiting for the technician, yes i'll probably have to, but as i have the parts to basically replace the unit, and have gone without heating for nearly three days, and based on past experiences will do for another 2 days minimum, i'd like to try other options while i wait.

Wearb

change the coupler. A pump freezing up will also damage the coupler.

Cass

shane0007 wrote: »

I would change it to try as if you are days from a technician calling & need the heat on, it maybe worth it.

Thats my thinking.

DGOBS wrote: »

Reset the burner, let it run to lockout, once it has, remove it from the boiler and see is the blast tube (front piece of the burner) wet with fuel. Come back to us with the answer, it will start us down the right path.

Done this earlier today. Fuel is being "sprayed" through the nozzle. Seems to be an ignition issue.

Also forgive my incorrect terminology. I may refers to certains items as "thingies" "valves" or by other incorrect terms but it's down to lack of knowing the proper terms for them.

Your burner sequence should be, from start of motor 12 seconds then fires up, or after 5 more seconds lock out (in simple terms)

I'm getting 5-6 seconds then lock out. Actually might seem shorter so could be 10+ seconds but always lock out. Never igniition/start up.

Wearb wrote:

change the coupler. A pump freezing up will also damage the coupler

For the sake of the ignorant (me). How will this make a difference? I'd like to understand why as well as possibly fix the issue.

Thanks.

DGOBS

If from motor start to lock out is 5-6 seconds either it's a control box, motor (just pondering on the fan being seized, is the motor shagged and not sending 50v back to the control box) or sometimes have seen the PE cell play the same trick on the control box (strange one I know)

But if lockout is after 5-6 seconds, the blast tube should be dry, as solenoid would not have opened before 12 seconds passed

Also, if getting fuel (after 12 seconds) check your spark gap and distance of electrodes to nozzle are correct (not too close, or not far enough that they are arcing on blast tube) after that it's air, do not adjust without proper test equipment, and just a thought, you changed the pump, what was the oil pressure (could be too/high or low, you'll need a pressure gauge to check)

Sorry for all the run around, but without test equipment….well….

DGOBS

If the coupling was worn, then once duty comes on the pump the dog would slip and you'd get low or no oil pressure (as motor no longer rotating the pump)

Wearb

The plastic coupler is designed to fail if the pump freezes to protect the motor. But if you are getting lots of oil at the nozzle, then it may not be that, but I would alway replace the coupler when replacing a pump. It can sometime be difficult to see the slight rounding of the "D" shaped slot.

Cass

No point in pretending. I don't know the ins and outs of the system. The little i do know is from trail and error/common sense. IOW i replace what i can, and leave what i don't know about alone.


To me, and again i don't know for sure, it can only be one of three things.

• Photocell (tried new and old one to no joy)
• Control box (have a new one and am considering taking the enitre unit out, changing over the control boxes and re-installing)
• Some other issue i haven't nailed down/don't know to look for.

In relation to the fan. It was partially seized in that it was tight, but a run with my hand got it moving without a bother, and a small application of greasing/lubrication has seen it running fine. Never had a bother before with it, and not since.

Wearb

DGOBS wrote: »

If the coupling was worn, then once duty comes on the pump the dog would slip and you'd get low or no oil pressure (as motor no longer rotating the pump)

Had one that ran poorly with a worn coupler. It gripped and released alternating rapidly between the two. Most noticeable thing during this sequence was a vibrating noise from the fan.

Cass

DGOBS wrote: »

Sorry for all the run around, but without test equipment….well….

I appreciate the fact that there are professionals for a reason and in previous instances i've stood back, and let them at it. However with circumstances as they are, the already 3 day without, and looking at 2-3 days before i see a technician i just thought i'd ask.

I also understand that it may be an easy fix, but unless you can see it yourself you are reliant on my observations/posts to understand the issues which is never ideal. I've had the system in for 7 years (the house is only 7 years old) and it's never given me any trouble. Just the last few weeks/months have been a bit of a pain. Not sure why, but i've almost replaced everything. As i replace something and get it going, something else goes. Not sure if it's wear and tear or someone looking to drive me to the looney bin, but either way it's working.


Thanks for all the responses, and while it's a bit late to go at it tonight i'll see what the technician says in terms of when he'll get here. If it's sooner than expected i'll have parts for him. If it's later i'll use what advice on here i can use and change some components myself. If all that fails then it's a matter of more blankets until the tech gets here.


Thanks to all.

jimf

any chance you got water in your oil tank might be a longshot but possible

would you be confident in your oil supplier

Cass

So was in town this morning and a friend of a friend got talking to me. Turns out her brother in law is a technician. My normal guy told me this morning it'd be Wednesday afternoon or Thursday before he got to me. Anyway she rang her brother in law, and he was in the area, and said he could drop out around 1pm.

He has just left and my system is up and working again. As said above i don't know the specifics about the system but he saw the new pump and immediately asked about it. Told him it was a new one i fitted the other day. I told him the fuel is flying out of it whereas the old one only allows a trickle. He went to his van, took out another pump and installed it. The system fired up immediately.

Now to me they look the same and are the same, but obviously there was an issue with the other new one i installed as he done nothing else and it fired first time. So happy days.


It's a testament to using professionals. Yesterday i, mistakeningly, would have sworn (and did) that the issue could not be the fuel as i could see a very visible difference between the old pump and the new one i installed. Turns out it just doesn't work the way it should on my system.


This guy was polite, quick, and got to the problem immediately. He tested the system after installing the pump and said everything else is fine (pressure, flow, other parts). He also only charged for the pump as a favour so kudos to him for that.


So thanks everyone for their help last night. Just wanted to let ye all know i got sorted.

Wearb

glad you got it going. thanks for reporting back.

Wearb

Re image; Is it acceptable to quote net efficiency figures for a SE boiler?

agusta

Wearb wrote: »

Re image; Is it acceptable to quote net efficiency figures for a SE boiler?

http://www.kane.co.uk/tech-tips-faqs/389-boiler-efficiency
This might help

Wearb

agusta wrote: »

http://www.kane.co.uk/tech-tips-faqs/389-boiler-efficiency
This might help

Thanks. Great article, but it makes my point rather than explain it. Therefore nett values should not be used in SE boiler efficiency settings???

shane0007

Wearb wrote: »

Thanks. Great article, but it makes my point rather than explain it. Therefore nett values should not be used in SE boiler efficiency settings???

Net values cannot be used for SE boilers because you are not recovering the latent heat from the flue gases, thus gross (total) is being omitted to atmosphere.
Net is used for HE boilers because the secondary heat exchanger is recovering the latent heat.

Wearb

shane0007 wrote: »

Net values cannot be used for SE boilers because you are not recovering the latent heat from the flue gases, thus gross (total) is being omitted to atmosphere.
Net is used for HE boilers because the secondary heat exchanger is recovering the latent heat.

Yes. That is my understanding also. That is why I question Grants use of nett on this threads boiler range.

agusta

Wearb wrote: »

Yes. That is my understanding also. That is why I question Grants use of nett on this threads boiler range.

Ah i have it now,I was looking for the image. You have the grant image on a different thread i think

shane0007

Wearb wrote: »

Yes. That is my understanding also. That is why I question Grants use of nett on this threads boiler range.

They are using net efficiency on the boiler efficiency. For analysis, we are dealing with combustion efficiency when we only use gross for SE boilers & net for HE boilers.

When talking about boiler efficiency we are talking about seasonal efficiency.

Wearb

agusta wrote: »

Ah i have it now,I was looking for the image. You have the grant image on a different thread.

I just realised that agusta. Sorry for the run around.

agusta

I looked at the grant image again.For a grant 50/90 boiler its giving a flue gas temperature of 223 degrees and yet its giving a net efficiency of 93.2 percent.If this figure 93.2 percent is boiler efficiency i would have thought it should be less than combustion efficiency.At a guess below 85 percent

Wearb

agusta wrote: »

I looked at the grant image again.For a grant 50/90 boiler its giving a flue gas temperature of 223 degrees and yet its giving a net efficiency of 93.2 percent.If this figure 93.2 percent is boiler efficiency i would have thought it should be less than combustion efficiency.At a guess below 85 percent

Assuming all latent heat is extracted, I think there would be about a 10% difference between gross and net.
What is your opinion on grant using nett figures on SE boilers?

jimf

Wearb wrote: »

Assuming all latent heat is extracted, I think there would be about a 10% difference between gross and net.
What is your opinion on grant using nett figures on SE boilers?

do a little exercise youself the next se boiler you do switch from gross to net during fga and you will find approx. 8% in the diff

shane0007

Wearb wrote: »

Assuming all latent heat is extracted, I think there would be about a 10% difference between gross and net.
What is your opinion on grant using nett figures on SE boilers?

Generally, manufacturers generally use net efficiency on all boilers. If that manual you have posted is a SE boiler, then it is incorrect as at that efficiency, it would make it a Band A boiler which is HE. So me thinks that manual is a boo boo manual.

jimf

they quote net in all the manuals for se boiler I have they even quote the multipass 70/90 as been 96 % net who needs a vortex