HTP Munchkin Boilers

HTP Munchkin Boiler Overview

The Heat Transfer Products Munchkin is a discontinued fully modulating gas boiler with an efficiency of 90% AFUE. It featured a stainless steel heat exchanger for optimal heat transfer and resistance to corrosion, and its compact, lightweight design provided greater installation flexibility. An Inconel NIT burner and spark ignition assured reliable operation, while a self-diagnostic microprocessor control monitored the system and made servicing easier.

Later versions of the Munchkin boiler include the Munchkin R1 (Revision 1), featuring a digital display and upgraded burners, and the Munchkin R2 (Revision 2), which differed from previous units because of its wiring and metal latches.

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Consumer Reviews of HTP Munchkin


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #4 of 12 HTP Munchkin Boiler
  • 26.67% of customers recommended

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HTP Munchkin Boiler Reviews

Showing 1-5 of 30 reviews


5.0 rating
Very Satisfied

After 12 years, first failure last night. Low pressure switch failed. Jumpered it and boiler fired. New pressure switch on the way for $26.
So this boiler is costing me $2 per year to run. ( not counting my time)



1.0 rating
Very Unsatisfied

An over-engineered piece of junk. Don't ever buy one. They need lots of maintenance thought! The one's, a honeywell furnace, we took out were there for 30 years without issue. It stops working displaying faulty codes. Technicians disassemble the furnace, couldn’t find things wrong and put things back and starts the furnace. This happens in monthly bases. I can't even being to describe the nightmare it's been and the money we have lost. Boilers should last for many years certainly not just 4 or 5. Also a company should stand by its product and if it gets discontinued they should replace it. I'm furious does anyone know what to do? If you do not want to rebuilt the entire boiler over every 4- 6 years, then stay away.

S. Hoshi

"16 Years"

5.0 rating
Very Satisfied

Had this installed in 2003 to heat 5000 sf including domestic water. It had a few issues that I was able to figure out (new board, fan, electrode a few times). My brother has a smaller house and uses 2 regular Water heaters and 2 he furnaces. He keeps parts of the house unheated and still pays more than me in my toasty house (live in the same town). When properly installed and maintained, the Munchkin is hard to beat.

Ramy Mughannam

Petaluma, CA

"Lived 11 years"

2.0 rating
Somewhat Unsatisfied

Paid top dollar to learn it broke all the time because it was "sensitive" !? Constant breakdowns, three gas valves, backfiring so loud would shake the whole house and scare neighbors. Spent 260$ to find out was dead as the last laugh. Bought a Bosch Greenstar, put it in today. Combi unit so no indirect water heater anymore either

Citizen of New York state


"Quite Happy with Mine"

5.0 rating
Very Satisfied

My Munchkin 80m was installed in 2002 and has pretty much worked extremely well ever since. In about 2014 the blower was replaced, but other than that I have had no problems. I get a maintenance visit for cleaning about every 3-5 years. I would definitely consider buying another HTP product based on my experience with this Munchkin.

Joe Stevens


Other Munchkin Reviews

Many of the comments regarding problems with the Munchkin have to do with them not firing properly. A professional on said that he’d done many service calls on the units and almost all of the problems were due to the gas/air mix not being set right.

Question and Answer


What does a Munchin fault code F-02 mean?


According to page 63 of the Munchkin Gas Fired Boiler manual:

Fault Code F03 description: “Interrupted or Shorted Return (Inlet) Thermister.”

To fix/remedy the problem:

  • Check the electrical connection to the thermister on the outlet manifold. Verify 5 VDC by checking in Molex connector. Verify thermister values by referencing chart in this manual.
  • Replace thermister if necessary.

Munchkin Warranty

The warranty for the Heat Transfer Products Munchkin boiler is comprised of the following:

  • Complete 1-year warranty on defective parts
  • Limited 3-year blower motor warranty
  • 12-year heat exchanger warranty, pro-rated after the 7th year

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