Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: nlh1250 on June 20, 2011, 12:55:23 pm

Title: front furnace overspeeding
Post by: nlh1250 on June 20, 2011, 12:55:23 pm
The front furnace on our 98 u295 has been very noisy since we purchased the coach in 2008.  We have had the motor replaced, three different blower wheels put on, and a vertical brace placed between the blower wheel and the combustion wheel, all to little effect.  Today I disconnected from shore power and suddenly the blower is much more quiet.  re-connected and a noticeable increase in blower speed was heard along with a annoying rattle of the counter top and microwave.  I checked  with Atwood Ind. and they didn't have a clue.  Called James T. at FT with similar results. The Heat interface indicates 13.70 volts,  The house batteries are cool and 3 years old.  A Trik-L-start unit is in place.  I don't have the equipment or knowledge to check the converter output  to see if it is overproducing.  Any suggestions would be appreciated.  Norm H.
Title: Re: front furnace overspeeding
Post by: wolfe10 on June 20, 2011, 01:10:45 pm
13.7 VDC is on the high side if the coach has been plugged in long enough for the charger to reach FLOAT voltage. 

Start by pulling out your inverter/charger book and make sure that it is properly programmed/dip-switches set.  If, for example, it is set to cold temperatures, it may be doing what you asked it to do.

And all motorhome owners need a digital voltmeter-- they start under $20 and are not difficult to use.

Brett
Title: Re: front furnace overspeeding
Post by: John Cooper on June 20, 2011, 04:07:20 pm
Brett is right.  The blower motor is 12 volts DC.  The higher the voltage the faster it will run.  Once you get a digital voltmeter, see the link below, check the voltage to the motor with and without the shore power hooked up.

OEM/Multimeter measure AC/DC voltage, DC current and resistance, diode test and (http://www.autozone.com/autozone/accessories/OEM-Multimeter-measure-AC-DC-voltage-DC-current-and-resistance-diode-test-and-low-battery-warning-and-input-impedance-for-voltage-10-MegOhms/_/N-26lr?counter=8&itemIdentifier=900834_0_0_)
Title: Re: front furnace overspeeding
Post by: nlh1250 on June 20, 2011, 04:29:23 pm
Holy Moley!!!  I can't tell you how much $$ I've spent on this front furnace, both locally and with FT and MOT and nobody during all that time ever suggested checking the inverter settings.  I looked for the manual and naturally it was not with my other data. (only had the coach -3 years) and neither was the manual for the link 2000.  I looked them both up on the net and got the PDF manuals, reset the charge volts and times for glass batteries,---- and the rest is history  Now working at a much slower speed and NO VIBRATION.  Thanks guys for the quick, accurate response 
Title: Re: front furnace overspeeding
Post by: wolfe10 on June 20, 2011, 04:41:07 pm
Excellent.  Glad it was that easy.

BTW, EVERYONE with a quality inverter charger should reprogram at least twice a year, since temperature is one of the variables.  Set on winter/cold in the summer WILL overcharge the batteries.

This does not apply to those whose inverter chargers have an on-battery temperature probe which makes the temperature compensation automatically.

Brett