Mastertemp Heater Igniter Resistance?

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wpbucher

wpbucher

LifeTime Supporter
Feb 7, 2012
150
South-Central Pennsylvania
I tried to fire up my Pentair Mastertemp 400 heater yesterday, but I couldn't get ignition. Start sequence:
1. Blower comes on 2. Here a click 3. Smell gas. This repeats three times and then the "service heater" light comes on. I thought that perhaps there was air in the gas line. So I did this several times....waiting 5 minutes between. No luck.

So I try to troubleshoot. I read the manual. I pull the panels. to gain access to look at the LEDs on the board and the flashing light on the ignition module. I turn on the heater...and it starts!!! So I stop the heater, replace the panels, set the valves to heat my spillover spa, and started the heater.

I figured it was air in the gas lines. The heater ran for about 30 minutes. I figured 30 minutes of operation would have surely purged any air in the gas line.

When it reached temperature, the heater shut off. It didn't, however, come back on.

After getting dried off, I tried to start the heater and had the same results (blower, click, smell gas). So I pulled the panels and attempted to start again....thinking maybe there is an air flow problem. No luck.

No LEDs lit up. The control panel light flashed three times. This indicates an "Ignition Lockout" condition.

So i disconnected the wires to the igniter and test with a multimeter. Note: I'm not extremely comfortable with the multimeter...but I think I'm competent enough to check resistance. Anyway, I think I successfully tested and got a reading of 95 ohms.

While researching, I found this very slow and boring video:
https://www.youtube.com/watch?v=J_efWFDlQVg

It states that on some igniters the range is 50-90 ohms. 50 is good and at 90 they need replaced.

I then found some instructions from Pentair:
http://www.pentairpool.com/pdfs/MasterTemp.MaxEThermHeaterIgnitor.pdf

It states that anything from 50-500 ohms is OK. From what I've been able to gather online, this seems like a very large range for an igniter.

Help!!!

Am I on the right track?

At what level of resistance should I replace the igniter?
 
I have had readings all over the place on many ignitors. For me the best thing is to actually pull the ignitor and see if it looks good or not. I have had numerous ignitors where they seemed to visually look good, but upon very close inspection I can see cracks in it. Thus it will not function like it should. Your issue could also be the control module. To check this, you would disconnect the ignitor and put your leads from your meter on it and set it to volts. Then turn on the heater and see if the module is sending out the correct voltage to the ignitor. If it isn't, the module is having issues.
 
Edit: when i typed this, no one had replied. Paul snuck in ahead of me!

It is probably the igniter. If the heater is still under warranty, have it looked at. If not, try to fire the heater cold (im assuming this is when you are getting the resistance reading). If it fires, turn it off. Repeat this until the heater will no longer start, then take your resistance reading. If your igniter has failed, you will get infinite resistance. What i think may be happening is you have a crack in the igniter. When the igniter is cold, you have a connection, and you are getting resistance and it is working (glowing). When it heats up, it expands a little, probably not enough to see, that's why at this point you check with a VOM to see if there is still continuity. If it is open, replace igniter. Access to the igniter is not hard, you just have to dig a little for it. It is just two nuts when you get to it, and of course the power connection. If it gets to that point and you get the igniter out and it looks like there is no crack in it, snap a pic of it and post it so we can look at it. Cracks are not always obvious. They will have some white crust or scale surrounding them. Sometimes this is all you will see (no visible crack).
 
I think I will try checking the voltage from the module.

The user manual says 120 vac is going to the igniter.

Thus I should set my multimeter to 250 as shown in this picture:

Multimeter.jpg

I'm just asking to make sure. I don't want to damage my multimeter...or more importantly the heater!!!

Thanks for your help.

I know my multimeter is ancient. If you could suggest a simple, reliable, forgiving (read idiot-proof) multimeter...that would be great.
 
I hooked up the multimeter. It showed 120 vac when I turned on the heater. I ordered the igniter. Awaiting delivery. I'll test resistance of the new igniter....and post pictures of old igniter.

Any tips for installation? I know don't touch the part that heats up. I'll wear nitrite gloves.
Should I put high temp grease on mounting bolt threads?
 
wpbucher said:
Any tips for installation? I know don't touch the part that heats up. I'll wear nitrite gloves.
Should I put high temp grease on mounting bolt threads?
Click to expand...

You can wear gloves if you want, or you can just hold the igniter from its wires. Actually, its easier to replace it if you dangle it from the wires and slowly lower it into position. You'll see what i mean when you get in there.

The replacement part will come with a new felt gasket, use it! The old one may look ok, but it is smashed and if you don't get a good seal (NO RTV, JUST THE FELT) fire box gases can escape through the leak and you can, over time burn a hole in the fire box that will grow and grow and, well, you can imagine what will happen eventually.
 
New igniter arrived. It showed 50 ohms resistance.

I removed the old igniter. Here is a picture:
View attachment 35621


I installed it with many contortions. I hate my PB. Who runs pipe that close to a heater?

View attachment 35619

View attachment 35620


Anyway, I removed old igniter. The old gasket stayed in place. When I tried to remove it kind of disintegrated. So I took a piece of wire and my vacumn and sort of scraped and sucked the old one out. That seemed to work OK.

So I installed the new igniter with new gasket and turned on the heater. It fired up on the first attempt!!!!

I then waited for it to turn off (93 degrees). I then increased the spa temp to 95 to cause the heater to begin heating.

Same result as before. It attempts to light...but nothing. Same results as when i started :( It tries to light three times...smell a little gas.....then service heater light comes on. Light on ignition module blinks three times (ignition lockout).

Since I have the same exact problems, I don't think the issue is igniter related.

The only time I've gotten this thing to light is after I've had the panels off for quite a while. Not sure if that has anything to do with it. With both the old and new igniters, I have gotten it to fire up...but only after the panels were off for some time.

Maybe an air obstruction somewhere? The inside of the cabinet is fairly clean...although a little spider could make a nest somewhere where I can't see it.

So I decided to do more testing. I figure I'll try removing the panels and waiting 30 minutes before attempting to start heater. I'm trying to isolate the removal of panels....so for a baseline, I decide to start heater with panels in place. Voila...the heater starts. I allow it to run to heat spa from 57 to 71 degrees and turned off the heater. I then waited 5 minutes and attempted to start the heater. Heater would not start.

More info. I noticed in the manual that the minimum flow rate for a 400 is 40 gpm. That seems like a lot of flow. We have been using the heater for 2 summers with a flow of 15 gallons. When I started the heater the last time the filtration flow was about 27 gpm. I turned off the heater and increased the flow to 30 gallons. When I tried to restart the heater...it wouldn't restart.


Any ideas???.....or is it time to call a service tech?

Thanks for your help.

Any other ideas?
 

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It just occurred to me that instead of contorting myself under the pipes....I should have removed the lid for easier access....DOH.

Just went out to try a "cold start"....and the heater fired up.

Thus we might have had two problems and now have one.

We had two problems: (1) a weak igniter...near the end of its useful life and (2) no restart when heater is warm

I replaced igniter. I've now had 3 successful "cold starts"....so we are left with a single problem: heater won't ignite to maintain temperature once warm.

Thanks for your help.
 
Seems like when the Fenwall heats up (just being inside the heater), it fails. I would change out the Fenwall, but that's me. I have the luxury of being able to swap out parts. So would a tech that you may hire to fix this. Diagnosing on the internet can only go so far sometimes, then its up to the owner what to do next. Next is usually spending money on a chance fix part, or hiring a pro and paying his labor.

BTW among a few other things the Fenwall is a switch that sends high voltage to the igniter. It is rare, but the Fenwall does fail.

If you smell gas, while trying to light, that means the heater is saying "all my safeties have been satisfied, lets light". At that point, it should only be two things, the igniter not dealing with the voltage correctly (no glow), or the Fenwall isn't sending voltage to the igniter. You replaced the igniter, and its not likely you replaced a bad one with another. So that leaves the Fenwall.
 
If you have to do something like this to the unit, it's junk. It clearly shows that the manufacturer has issues and thus I would avoid them. What's next, stick some duct tape on the air orifice as it's sucking in too much air.

wpbucher,

Just out of curiosity, have you removed the bottom bolt on the manifold to see if any water comes out? If not, just check and see. Water in the can will do some strange things with the unit lighting and what not.
 
Solving ground path and rectification issues have been something that have plagued all heaters since the invention of IID's. Even Raypak has problems with their pilots and ground path. Saying it's junk is a little harsh. Now the recent laars/zodiac/etc heaters might fit in that category.,
 
Not harsh but truth. I have not had any issues with the Raypaks\Rheems with regards to the pilots and ground path. All units have their issues but from my perspective with all the repairs I do, Mastertemp and Sta Rite are tops on the list with the Hayward FD heaters coming in close behind them. Of course, this is just my opinion from my experiences in the field.
 
So I tried again. Fired first time, would not restart. I checked the igniter 50 ohm resistance and the voltage coming from Fenwall 120v. I then came in and checked this thread to see if there were any updates. Two ideas. Ground and water in the can.

Since checking if there was water in the can was easiest, I thought that I would try that first. I removed the drain plug and this is what happened:
https://www.youtube.com/watch?v=52fLGIvblc8

So I drain the water and put humpty back together and fire it up. Fires up first time....second time not.
I then check if there is water in the can by removing the drain plug....same thing...about 1/2 gallon of water comes out.

I also noticed on the first drain that it sounded like other things were draining. Upon restart...I got bubbles out of the returns.

So now I'm thinking (watched Full Metal Jacket last night) that "I'm in a world of s**t"!!!
https://www.youtube.com/watch?v=xnTU4dKpoB8

Does this mean the "tube sheet coil assembly" has leaks/holes in it????

Just checked Amazon....$647 for a new one......ACK!!!

Is this because the no-good-son-of-a-gun-PB didn't install a pressure relief valve????

Please tell me there is some other less expensive explanations......please!!!

Thanks TFP.....this pool thing sure does get expensive sometimes....
 

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