Heating Guy says go Monitor Kero system?

[LarryNH914]

Situation:

1) Damp crawlspace (there is plastic on the floor).
2) Rusty FHA Oil Furnace.
3) Horizontal installation (around 4' of space)
4) 2nd Heat exchanger cracked in 7 years. (I suspect corrosion due to damp environment)
5) Maine (along coast, so unusual to get to -10F, but it does)
6) Around 1500 square ft.

The small independent HVAC guy that replaced the exchanger last time is suggesting that a "pattern" has emerged, and that we should consider using Monitor type heaters instead of the central system we have now.

We would use 2 Monitor type systems. (Actually, I am leaning toward Toyotami systems since you can use #2 oil if we do this)

I can see his point looking at the 10 year old furnace that looks 10 times worse than a
furnace I have in a townhouse in a nice dry basement that is probably 25 years old. For example, we had to replace the chimney pipe because it was almost corroded through.... If you dig a hole in this crawlspace, it fills with water. I think most corrosion occurs in the summer, when the system is not being used.

But.... most Monitor type systems I see are called "supplemental".

There may be a problem with not enough return air (could this cause a heat exchange to overheat??) as well, but this could be fixed.

So, just keeping an open mind right now and asking questions. The Monitor type approach is not typically used as a main heating source, so I am a bit uncomfortable about this.

Are there furnaces designed for this kind of dampness? Is there a reason I should not consider the monitor approach? We don't have a great place to put a system on the first floor.

Thanks,
Larry

[sktn77a]

There may be a problem with not enough return air (could this cause a heat exchange to overheat??) as well, but this could be fixed.

Absolutely! If your temperature rise is too high (due to lack of airflow) this doesn't bode well for heat exchanger longevity. I would get this checked before ripping the system out and buying a whole new set of problems!

[LarryNH914]

Absolutely! If your temperature rise is too high (due to lack of airflow) this doesn't bode well for heat exchanger longevity. I would get this checked before ripping the system out and buying a whole new set of problems!

Thanks for the reply. Makes sense... This system was clearly designed by either a dumb-ass or a former owner (But I repeat myself, don't let me get into the wiring, where I found rats nest connections in the walls, outside a box, without wire nuts)

But, I would need to rip out the existing furnace anyhow. (not worth replacing the heat exchanger on such a rusted system? Or am I wrong here.).

If I went monitor, I would probably not rip out the rest of the existing system, just cover the vents.

Oh, the HVAC guy thought that the problem could be horizontal systems themselves are flawed.... I am quite certain that horizontal systems work fine, but then I am not a HVAC guy.

So, I am between the problem of a bad environment for a new Furnace.... Or a Monitor style system.....

Or Get a new furnace and try and fix the environment some how. (large space to dehumdify... Do they make enclosures for furnaces that would help keep the damp out?)

[t527ed]

i would go with new furnace and fix the environment.

ventilation or good dehumidifier for the summertime.

[mchild]

Larry,

Here is a recent discussion on crawl space issues and what to do about them.

http://hvac-talk.com/vbb/showthread.php?t=347672

[wahoo]

Use a high efficiency (90% plus) sealed combustion (two pipe) horizontal furnace in this damp crawlspace. This will keep the moisture out of the burners and ignition parts. As to the Monitor system, I'm not familiar with this unless it is some kind of radiant, unvented heater. If it is an unvented system, don't go there for primary heat, as all of these units creat carbon monoxide, and can create un-safe amounts if used for primary heat. We only use sealed combustion units in crawls, as open furnaces won't last. Oh yeah, make sure and cover the dirt crawlspace floor with plastic, and ventilate to reduce moisture build up.

[jeepgrady]

Had a Monitor kero system for twenty years when I lived in Pa. Great technology. It's a vented system I used it as a supplemental tor heat my entire finished lower level in my b-level. The heat also went upstairs. Used only about 150 gallons per year.

[pacnw]

I am not 100% sure, but the use of #2 or #1 oil would depend on the location of the oil tank and lines for either system.

I believe Monitors can use either and so can the Toyotami.

[LarryNH914]

Thanks for the thoughtful replies... Sealed unit sounds good. We did cover with plastic, but will defiantly keep the 4 windows open in summer from now on! Will add a return air vent as well....

If we went the monitor, it is vented through the wall. I did read you can use #2 on toyotomi, but then you must service and clean more often so many don't recommend it.