HTP, or Heat Transfer Products introduced the Munchkin line of high efficiency boilers in the early 2000’s. Many of these boilers have been installed in Calgary and southern Alberta. Popular models included the T50, T80, 140, 199M boilers.
As with most high efficiency boilers, if properly installed, set up and maintained over time, they were reliable heating systems.
The service issues encountered with this boiler design includes dust and moisture being drawn into the cabinet through the combustion intake pipe. The cabinet design offers little protection in the form of internal baffles or an enclosure for the boiler controls. The internally mounted boiler control has service life issues when dust, debris and moisture is deposited on the controls and insulation blanket covering the heat exchanger. In many cases the dust and debris in the intake air stream leads to the premature failure of the swirl plate.
Problems with the swirl plate in the Munchkin boiler eroding prematurely was an issue from the onset. The chances of swirl plate erosion was compounded with poor maintenance practices including improper cleaning of the boiler cabinet interior during annual maintenance.
The damage to the vanes on this swirl plate on a Munchkin 199M inducer assembly is visible in the picture. This is an obvious design fault, yet in many cases the erosion is blamed on exhaust gas recirculation issues. And while some swirl plate deterioration was caused by the corrosive nature of the exhaust gasses when recirculation was occurring, most problems were from the dust and debris.
The Munchkin 199M and 399M high efficiency condensing gas boilers require an internal inspection and cleaning of the heat exchanger at least every 24 months, especially on those systems that work year round during DHW (domestic hot water) demands.
The Munchkin boiler series has been discontinued by HTP and should one of these Munchkin high efficiency condensing gas boilers be in your home, be sure to have it serviced on a regular basis.