Laser 730 over firing

[hawkins111]

Has anyone had an occurrence of a Laser 730 or 731 over firing?
The top of the heat chamber and the heat exchanger glow red on high when this occurs.

[machinist]

Hi Hawkins111!

No but generally, over firing can occur when there is issue with fuel flow rate or air-to-fuel ratio. Have you checked the fuel filter and fuel nozzle? I am not sure if these models have screws for adjusting fuel flow. If yes, you will need to check that too.

If the fuel flow rate is optimal, you have to move towards air flow. Check the combustion blower for any dirt and debris. Check air intake and exhaust vent for any obstructions.

Other possible cause can be issues with burner pot and combustion chamber. Last but not the least are the sensors and control board.

Let me know where are you with your diagnosis so we can find the culprit.

[TinyTool]

This can be caused by a few different factors, here are some things to check:

1. Fuel Flow Too High: If the heater is getting too much fuel, it can cause excessive heat, leading to over-firing. This could be an issue with the fuel feed or the burner pot. You might need to have the fuel flow calibrated or adjust the fuel feed mechanism to ensure it's not over-delivering fuel.
2. Airflow Restrictions: Poor airflow can also cause overheating. Make sure that the intake and exhaust vents are clean and free from blockages. Sometimes, filters or the venting system can get clogged, restricting airflow and causing the heat exchanger to overheat.
3. Carbon Buildup: Over time, carbon buildup in the burner pot or heat exchanger could interfere with proper combustion. A thorough cleaning might be necessary to ensure the system is running efficiently.
4. Faulty Sensors: The thermistor or flame sensor may be malfunctioning, causing inaccurate temperature regulation. If these sensors aren’t reading the temperature properly, it could result in the system burning hotter than intended. Replacing or cleaning these sensors could help.

[hawkins111]

Sorry, I didn't explain the issue very well.

I know the cause of the issue of over firing. I just want to hear from anybody else that has had the issue. Laser 730 or Laser 731 have been having over fire issues in our community since they came out. I want to know if the issue is system wide or just in our area. If its only in our area then this could be a fuel type issue.

[machinist]

Oh, strange. Sorry have no first-hand experience with Laser 730s. I tried searching online to find anyone facing similar issues, but couldn't find anything.

[hawkins111]

Now that I have been advised of a unit over firing on the East Coast, and one more in
Bethel Alaska, it is apparent that this is a Laser 730, Laser 731 issue.

The unit I just serviced in Bethel had been over firing for over a year. This unit was installed by the purchaser and had other issues as well. Once the unit was serviced and fuel flow was reduced the high flame was reduced, but not completely removed.

The unit in Bethel Alaska would not be eligible for a Warranty, as the unit was improperly installed and the time limit had been exceeded.

If you purchase a Laser 731 or 732 heater and plan to install it yourself, be sure to follow the instructions provided with the unit. If you don't follow the instructions completely you will Void the warranty.

The warranty of a Toyotomi product is a rare issue. The units sold by Toyotomi are very reliable and seldom need any service work right out of the box. There is a proper procedure to follow in the case of a warranty issue and will be covered in a separate post.

[TinyTool]

Thank you for the update! Your insights about the over-firing issue and the importance of proper installation are really valuable. I’m sure this information will be helpful to many others, especially those considering installing a Laser heater themselves. Looking forward to your post about the warranty procedure.

[hawkins111]

I have been notified of two more L731 heaters over firing. One has been in service for two years and needs a new burner pot and heat chamber. We will reduce the fuel flow through the indicator panel.

The other unit has been in service for about a year and has a very high flame. That unit has not been inspected as yet. If we can see the burner ring through the window and it's not cracked, we will be able to reduce the fuel flow and see if the flame goes away.

It is evident this is a problem with the entire line of Laser 730, L731, L732 series. If you have one and it has a high flame, contact your dealer and get the flame reduced or possibly have the whole unit serviced.

[Tomhanks]

That’s concerning to hear, especially since it’s affecting multiple units in the series. Over-firing seems to be a recurring issue with these models. Reducing fuel flow might help in the short term, but if it’s already causing damage to the burner pot and heat chamber, it does raise questions about the design. Hope the inspections provide some clearer answers!

[machinist]

That’s definitely concerning. It seems like over-firing might be a common issue with these models.

[TechEditor]

Since it has been about 3 months, I thought I had better give everyone an update. 1. Dealer won't help unless Toyotomi authorizes it. 2. Toyotomi won't help unless Dealer asks for it. 3. Dealer refuses to ask. 4. Upon disassembly, I found the Burner Mat was not installed correctly. So, I installed a new Burner Mat, Burner Ring and gaskets as seen here: https://www.youtube.com/watch?v=nq5d...=3&pp=gAQBiAQB
5. Burn problem solved but by this time the Heat Exchanger was warped and would not seal with a factory gasket. 6. I developed a gasket from the wood stove industry that would allow the Heat Exchanger to seal to the Heat Chamber as seen here: https://www.youtube.com/watch?v=iW15...=2&pp=gAQBiAQB
. Unit has been in operation for over 2 months now with the special gasket and no leakage detected.
Is it running as well as my old L73? No, never will. Way too much noise warming up and cooling down. But at least it produces heat and all the combustion gasses are now directed outside instead of inside!
I have started collecting used rebuilt parts to rebuild my L73 as a summer project, and intend to get the old girl back in operation. If anyone has a rebuilt blower fan motor for the L73 let me know. I have the almost new Burner Ring from the L732 that I think is all right but I replaced it anyway with a new one in the L732. And I have a rebuilt combustion blower from Ebay. So, with some new gaskets I will rebuild the L73 this summer.
What did I learn: Get a good Dealer that will stand behind you. When Toyotomi says you MUST have the Dealer install the heater, I guess you have to pay for it to be installed even if you are more than capable of doing so. When Toyotomi states you MUST install a new exhaust with a new heater (because that is why every heater comes with a new exhaust) that isn't always true. I removed mine and found nothing the matter with it after 19 yrs of operation in Northern NY. Installing the new exhaust per Toyotomi didn't help my problem which was due to the factory not gluing down the Burn Mat correctly and fuel got under the mat lifting it up in the air so I could literally peal it off the Burner Pot base!

[machinist]

Thanks for the update! Sounds like you went through quite a process to get things working, and it’s great that you found a solution, even if it’s not perfect. That issue with the Burner Mat not being installed correctly must have been frustrating, but it’s impressive that you were able to diagnose and fix it yourself.

The gasket solution from the wood stove industry is a clever workaround. 👍

Hopefully, your L73 rebuild goes smoothly! Keep us posted on how it goes, would love to hear how the L73 turns out!

[Nycpa1]

Good afternoon Gentlemen,

I’m having a situation with a 731 toyotomi which I had an installer install last year to replace my 21 year old monitor 2400. It had a smell in the house on startup, and after speaking with my parts supplier, we decided to replace it with the 731, for cost and WiFi capability.

About a month of operation, the heat exchanger started to really pop and bang, to be clear it isn’t the normal startup and shut down expansion noise. It popped and banged as it was pre heating then as the stove went in to high fire it would pop and bang again most of the time in high, slightly quieter as it heated up. When it was satisfied and modulated down to medium, it would pop and crack as it cooled down slightly. Same as it transitioned into low. After about a minute or so in low, it would quiet down, until shutdown and then became extremely loud popping and cracking. I spoke to the installer, he said it was normal. Lived with it for a month last year, however January of this year it was getting on my nerves so I made a few calls. The installer admitted he had a second one that did the same and he swapped out the heat exchanger and it went away. Said the distributor told him the welds were the problem in the exchanger.
So he swapped mine. Lasted about 2 weeks. Making almost the same noise as the first.

I called Toyotomi. The tech guy has an attitude. I think Mr Greg hall has dealt with him. His response is the unit is over sized and cycling too often and I’m warping the heat exchanger. He gave the installer the same advice

The toyotomi tech says the unit should be basically started in October and run in low fire until April.

It has different cycle times. Obviously the colder out the longer it stays on. On a 50 degree day, it might do a 20 minute on, ten off and restart, as I keep it set at 62-64.

Ive read your posts about the overfiring, I don’t see the exchanger glowing and the flame is nice and blue.

You guys seem to be knowledgeable, I don’t think it’s really short cycling and even if was, if two weeks warped the exchanger, then it really is a piece of junk.

How long in average do your heaters run during a cycle?

Also to just fill in the details, the monitor ran the same way for over 20 years and I only went into the burner once, doing a full rebuild.

I would appreciate any help and or insight. .

[hawkins111]

Nycpa1,

Yes, you have a heat exchanger problem. It more than likely is caused by an over firing issue in the burner. You may have to shut off the lights in the room and look at the junction of the chamber and the exchanger when its running on High. If there is a dull red glow, you have an over firing issue.

No, the issue will not go away on its own and it is not normal. Something is causing the heat exchanger or the baffle in the exchanger to warp due to excess heat. As the unit cools down on Low, you hear it again. When this happens, there is too much flame up high in the burner chamber. Either too much fuel, not enough air, or a blocked exhaust or exchanger.

I doubt the unit is over sized, but we can figure that out very quickly. What is the square footage of your house? Is the area your heater is in an open space, or a small room? Is your house well insulated? A bigger problem would be a space that is too big for the unit. If this is the case the unit will run on High for an extended period. The unit can carbon up around the fuel nozzle if it runs on High for a long time.

The Rural Energy Enterprise web site has a section
in their information on Laser 730 series heater that has service information on fuel pump troubleshooting. It is a little time consuming but it will show any issues with the fuel pump or Main Circuit board. I have had limited success with these two service bulletins. If you are not versed in the use of a Multi Meter, you may have to get some help. It would be real nice if your service guy would do it for you, but don’t get me started!! There is also a section on High Flame that you should read as well.

Please keep us posted on your efforts to solve this. The more informed we all are the better off we are.




Tom

[hawkins111]

Nycpa1,

Can you give us an up date on your Laser 731 over firing issue?

Thank you,

Tom