# Monessen CSVF30 LP - Pilot Won't Stay Lit



## ember1205 (Feb 1, 2014)

I'm looking for some insight into how to best troubleshoot this issue. The manual has information regarding what the MV readings should be across two different pair of terminals, but it isn't clear to me the EXACT conditions under which I should take those readings.

From the manual:

A. Complete Milli Volt System Check
(“A” Reading - Thermostat contacts CLOSED - Control Knob “ON” - Main burner should turn ON)
a. If the reading is more than 100 millivolts and the automatic valve still does not come on, replace the control.
b. If the closed circuit reading (“A” reading) is less than 100 millivolts, determine cause for low reading, proceed to Section B below.

Does this mean that I should have the switch "ON" (there is no thermostat connected), the burner on, and the stove lit? Not lit?

The "B" reading wants the Thermostat OPEN and the main burner OFF. I presume this basically means that the stove should be completely shut down?

Does the stove need to be connected to the fuel supply? And the valve in the on position?


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## sticks (Feb 2, 2014)

Save yourself some time . The only millivolt reading you need is on the thermocouple  which is welded to the pilot assembly. I would take an air compressor with a nozzle and blow around the pilot assembly.Blow back throughwhere the flame comes out. Also at the start of the ods piot assembly thereis an air mixer blow through that. I have  seen this  work for while done with a drinking straw. The compressor work better and you should go head and blow every every spot in that unit. There will be a ton of dust in there so have a vac running to catch it. I would where  mask .Also don't blow the dust off the logs use  a paint brush and brush them off out side stillwearig the mask.


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## ember1205 (Feb 2, 2014)

I'm aware of the process to clear the passages and such. I'm interested in understanding the exact method required to conduct the tests that Monessen has in the manual.

Also, for testing the TC individually, should that be tested connected or disconnected. And, how would you suggest heating it (method) to test the voltage when hot?


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## sticks (Feb 2, 2014)

i am not sure which brand of valve is on yout unit. Normally you would have disconnect the tc.Leave the gas hooked up and use the pilot as your heat source.


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## DAKSY (Feb 3, 2014)

IFIK, you have to have acces to the valve attachment end of the TC to take a reading on it. A Scripto butane stove lighter or a Bic will suffice as your heat source. To test it will probably require an extra pair of hands, tho. You need your multimeter - SET to vDC  - contacts at the extreme end of the TC & somewhere along the OD away from the end. Engulf about the top 3/8" of the TC in the flame & read your meter when the numbers stop climbing...


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## ember1205 (Feb 3, 2014)

Thanks, Daksy. Any guess as to what I should get as a reading when it's heated?

I can do the test solo if I use alligator clips for the leads of the meter. And, I know I have to be careful about where I attach at the very end so as to not cross the lines.


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## DAKSY (Feb 3, 2014)

Thermocouples designed for residential gas appliances, such as fireplaces, water heaters and furnaces, are made for 30 Millivolts. The reading should be between 25 and 30. Anything under or hovering around the 20 millivolts mark means the thermocouple needs to be replaced. Discretion should be used if the reading is between 21 and 25.


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## ember1205 (Feb 3, 2014)

That was what I thought. The tests documented in the manual refer to connecting to the terminals where the TC is connected and seeing a -minimum- of 325mv (which would be way off of the charts for the TC itself, and that's why I'm trying to understand EXACTLY how to execute their test where everything is still connected). And, that test is with the burner OFF. So, I have no idea what would be feeding the voltage to the system.


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## DAKSY (Feb 3, 2014)

Sounds like a typo. 325 mV is ThermoPILE generation...


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## ember1205 (Feb 3, 2014)

Maybe it's a goof on my part then as the manual does refer to a TP and not a TC.


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## ember1205 (Feb 3, 2014)

It seems that THEY don't know what it is. The drawing shows an ODS and a TC. The testing refers to a TP.

Here's a link to a manual that covers these stoves if you think it's worth a look to decipher: http://literature.mhsc.com/monessen/manuals/58D6002_CSVF_VFCS_8.pdf

Mine is the CSVF30 model, equipped for LP.


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## ember1205 (Feb 3, 2014)

Did some more thorough investigation with the manual and such, and here's what I'm seeing...

The "part" in question is simply referred to as an "ODS Pilot". It's a complete assembly with the frame, ignitor, ODS, and Pilot/TC combo. Yes... The TC and Pilot are actually one piece. Here's a picture from the manual that calls this a thermocouple, but I'm wondering if it's actually a thermopile as it has only one solid wire wrapped in insulation.


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## DAKSY (Feb 3, 2014)

If you've got an ODS, them you've probably got a non-vented appliance. Those pilot/ODS assemblies generally aren't serviceable & have to be replaced in their entirety..


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## ember1205 (Feb 3, 2014)

Yes, vent free...


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## ember1205 (Feb 3, 2014)

Ok... MORE reading... 

The "ODS Pilot" term is somewhat generic. All that it really means is that the Pilot itself is oriented in a way that, if the Oxygen level drops, the flame will migrate away from the tip of the pilot housing. As it does this, the flame moves away from the TC/TP, they cool, and the system shuts down.

It also seems that this system uses both a TC and a TP. The TC is controlling the fuel flow for the pilot while the TP seems to be controlling the fuel flow for the main burner. If the oxygen level drops, the flame migrates, and both the TC and the TP will cool. Both valves will shut down. If the flame moves only a little, the valve for the main burner will shut down but the pilot -could- remain lit. If the oxygen level continues to drop from just the pilot, the flame will move further away, cool the TC as well, and the whole system shuts down.

I've found some seemingly good info on testing the TP. Connect everything up, turn the main burner switch off. Read the voltage. It should read AT LEAST 300mv. Turn the burner switch on and the voltage should drop roughly in half. If it drops to zero (or near zero), the TP is bad and needs to be replaced.


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## ember1205 (Mar 24, 2014)

I got the plumbing installed and the stove connected. My testing so far has shown me that there's some sort of fault in the control valve.

The previous owner indicated that he was unable to get the pilot to stay lit. As part of his troubleshooting, he had a technician look at the stove and achieve no results. So then HE took the control valve apart, didn't "see anything obvious", and put it back together. At this stage, the following is what's occuring:

- Turn on fuel, turn control knob to the Pilot position, press in  and hold, click the igniter, the pilot AND the main burner both spring to life. The thermocouple appears to be working properly because you DO need to hold the Pilot button in for about ten seconds.
- I have completely disconnected the manual on/off switch that controls the main burner valve, and there is no difference.
- If I turn the main control knob back to the Off position, the pilot goes out but the main burner will remain lit for approximately 30 seconds or so. It will go out once the thermocouple cools and shuts down the valve.

My guess is that the previous owner must have somehow either mis-connected something upon re-assembly or somehow crossed a connection somewhere. Does anyone have specific information about what's inside of these control valves?

Also - there are two ports on the valve. One is marked "out" and is referenced in the manual as a port where you can slip on a piece of tubing and connect it to a gauge to determine if there is proper fuel pressure. There is no reference to the one marked "in". The manual states that the one marked "out" must be screwed all the way in for proper operation, and it appears that the same holds true for the one marked "in". But, I'm looking for confirmation on this.


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## DAKSY (Mar 24, 2014)

The IN port is for checking gas pressure TO the valve. The OUT port is for checking gas pressure THROUGH the valve.
You say that you've disconnected the ON-OFF switch...How are you trying to turn the unit on?


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## ember1205 (Mar 24, 2014)

The ON/OFF switch is what controls the main valve. The switch is disconnected, but fuel is clearly passing through the main valve based on the thermocouple temperature only. If I turn the control knob to the pilot position and light it, both the pilot AND the main burner light together - even with the switch disconnected. Turning the pilot control off will shut down fuel to the pilot, but NOT to the main burner - that does not shut down until the TC cools. And, that's what's making me think that there's a "crossed wire" somewhere inside of the main control housing.


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## ember1205 (Mar 24, 2014)

It gets more interesting... I unhooked the thermopile (I had been referring to this as the TC, but the TC does not connect to the electrical block) and the ON/OFF switch from the electrical block. I turned the dial to enable the pilot, pressed it in, hit the igniter, and the whole system lit. Turning the pilot control off did the same as before - pilot shut down, TC cooled, and then the main burner turned off.

It seems that there is a definite issue with the TC activating BOTH the pilot AND main valves. Is it possible that, when the previous owner reassembled the control valve, he installed something incorrectly?


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## ember1205 (Apr 8, 2014)

Ok... Purchased and installed a new control valve. New issue.

I light the pilot, hold the knob in for five seconds or so, and let go. Twist the knob to the "ON" position. After about 30 seconds or so of warm-up time, I can flip the control switch on the back of the stove and hear the gas begin to flow through the control valve for the main burner (this was most definitely NOT happening before). After about two seconds, I can smell the extra fuel, but the burner WILL NOT light. I have left the valve open for about eight seconds with no ignition of the main burner.

Two questions:

- The PILOT adjustment screw seems to have no bearing for me even though it would -seem- to be how I would adjust the amount of fuel flowing to the pilot itself (thus, adjusting the flame to burn correctly). Even in the completely closed position, the pilot will light and burn fine.

- How do I go about troubleshooting this? Any tips would be welcomed.


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## logguy2 (Apr 25, 2014)

ember1205 said:


> Ok... Purchased and installed a new control valve. New issue.
> 
> I light the pilot, hold the kn. S in for five seconds or so, and let go. Twist the knob to the "ON" position. After about 30 seconds or so of warm-up time, I can flip the control switch on the back of the stove and hear the gas begin to flow through the control valve for the main burner (this was most definitely NOT happening before). After about two seconds, I can smell the extra fuel, but the burner WILL NOT light. I have left the valve open for about eight seconds with no ignition of the main burner.
> 
> ...


The pilot adjustment screw has no effect upon most VF gas fireplaces. By adjusting the pilot, you alter the operation of the oxygen depletion system. It sounds like the pilot is not adjusted properly or is clogged.

 I suggest that you call a qualified gas fireplace professional. With vent free gas fireplaces, if you work on it yourself and get it right, you've saved yourself $120.......if you get it wrong, your house could blow up or carbon monoxide could kill your family 
Also, if you do happen to blow up your home due to you installing a part improperly, your insurance company probably will not pay.


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## ember1205 (Apr 25, 2014)

I appreciate the info about the pilot. If adjusting the screw impacts the ODS, do you have more information (or does anyone else for that matter) about how the adjustment impacts and how to determine an optimal setting? The last control valve had the screw out about 1.5 turns and this one came with the screw all the way in.

As far as the problem with not lighting, that turned out to be an issue with the wool and logs not being in place. Once the wool and logs were reinstalled, the stove lit right up and now lights very quickly and reliably.

One other question has arisen, though.. The pilot seems to "whistle" a bit. Basically, you can hear it burning as if there's an improper adjustment somewhere. Any tips on where to adjust this so that the burn for the pilot is optimized?


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## logguy2 (Apr 25, 2014)

Ember, there are many things that could cause pilot noise. It could be a damaged pilot assembly, the wrong pilot assembly, improper gas pressure........I would seriously look for NFI certified tech to evaluate your whole system. Make sure you tell him EVERYTHING that you or anyone else has done to this appliance. I have seen $17,000 in soot damage from unqualified people working on ventfree gas appliances.

 You can find one with this link. http://nficertified.org/pages_consumers/consumers-1.cfm


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