# Trouble shooting my Morso MV200



## garymaji (Feb 27, 2010)

I purchased (several months ago) a used Morso MV200 that worked at the time but doesn't now.  I've replaced the gas valve (the technician recommended this part) and installed a new thermcoupler and thermopile assembly unit to hopefully get the unit up and running again.

To my dismay, I still can't get the pilot to stay lit.  Both the gas valve and thermocoupler/thermopile assembly were sent direct from the manufacturer in TN.  The pilot knob on the value opens and allows the gas to ignite the burner, heating up both the pile and coupler.  But after several attempts the pilot will not stay lit!  Not sure what's left to replace on this unit.....

Thanks in advance for any advise and/or potential solutions.

Gary
303.941.4962


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## begreen (Feb 27, 2010)

Moved to the gas forum for better response.


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## DAKSY (Feb 27, 2010)

How big is the pilot flame? What's your fuel - LP or NG?
Visually, you need about 1" of flame engulfing the top 3/8" of the thermocouple (t-c)
to generate the millivolts (mv) required to make the (t-c) function.
Get yourself a multi-meter, & have somebody hold the "pilot" knob in & take a reading 
on the t-c to see if the pilot flame is generating enough mv to keep 
the magnets in the valve open. 
You will Porbably have to unscrew the t-c from the valve & put one multimeter probe
on the "button" at the end of the t-c & the other probe on the copper wire.  
You need a min of about 28mv, but 30-31mv is better.
If your reading is low, is there a pilot adjustment screw? If there is,
see if you can turn the pilot flame a little higher. 
If you can't adjust the pilot flame, you may have the wrong orifice in the pilot assembly.
If you CAN adjust the flame, the mv are low & it STILL won't hold the pilot, your T-C may be toast.
Probably confused the HELL out of you, but PM me if you need more input.


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## garymaji (Feb 28, 2010)

Thanks for the reply.  I knew I would eventually have to get out my mV meter sooner or later.  What really gets me is that both the pilot assembly and the gas valve are new replacement parts ordered from the manufacturer. Yikes!

First I'll see if I can turn up the pilot flame.  The pilot assembly consisted of the t-c, t-p, gas orifice and the ignitor unit.  The orifice where the flame comes from is set to Nat (I have an NG source) and has a cover that directs the flame to both the t-c and the t-p.

Regarding the use of the mV meter.....I assume I'll need to test the t-c while it is getting hot.  

Thanks again,
Gary


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## DAKSY (Feb 28, 2010)

gmm said:
			
		

> Thanks for the reply.  I knew I would eventually have to get out my mV meter sooner or later.  What really gets me is that both the pilot assembly and the gas valve are new replacement parts ordered from the manufacturer. Yikes!
> 
> *Ya never know with electrical stuff. ALWAYS fails when ya need it most*
> 
> ...


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