Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The MCA Pro 65 and MCA Pro 90 are adjacent condensing wall-hung sizes: 34–235 versus 55–326 MBH input and 45–222 versus 54–306 MBH output at the same 94.0% CSA thermal efficiency. Both use 4"/100–150 mm venting and identical 1-1/4" heating and 3/4" gas connections; the 90 adds about 84 MBH of maximum output with a slightly higher minimum fire.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | De Dietrich MCA Pro 65 | De Dietrich MCA Pro 90 |
|---|---|---|
| Minimum input (as printed) | 34 MBH | 55 MBH |
| Maximum input (as printed) | 235 MBH | 326 MBH |
| Minimum heat output | 45 MBH | 54 MBH |
| Maximum heat output | 222 MBH | 306 MBH |
| Thermal efficiency (CSA certified) | 94 % | 94 % |
| Firing | Modulating, on/off, remote 0–10 V | Modulating, on/off, remote 0–10 V |
| Heating supply / return | 1-1/4" male NPT | 1-1/4" male NPT |
| Vent / combustion air | 4" single pipe / 100–150 mm concentric | 4" single pipe / 100–150 mm concentric |
| Weight (dry / wetted) | 133 lb dry / 147 lb wetted | 148 lb dry / 165 lb wetted |
Both models are condensing cast-aluminum wall-hung boilers from the MCA Pro submittal Rv 5.4, sharing the 94.0% CSA thermal efficiency, 94.3% combustion efficiency, up to 98.2% usable efficiency and standby loss below 0.3%. The 65 prints 34–235 MBH input and 45–222 MBH output; the 90 prints 55–326 MBH input and 54–306 MBH output.
The minimum fire rates are close — 45 MBH output on the 65 against 54 MBH on the 90 — so in mild weather both modulate to a similar floor, and the 90's extra 84 MBH of top-end output is what the load calculation has to justify. Both sizes share 4" single pipe / 100–150 mm concentric venting, 1-1/4" male NPT heating connections and a 3/4" male NPT gas connection.
Physical differences are modest: dry weight 133 versus 148 lb and wetted weight 147 versus 165 lb, with the same 29½" height, 19¾" width and depth cabinet printed in the submittal. As with the whole line, both are certified for installation to 4,500 ft (Canada) and can be cascaded with other MCA Pro boilers.
De Dietrich
The De Dietrich MCA Pro 65 is a condensing wall-hung boiler rated 34–235 MBH input and 45–222 MBH output at 94.0% CSA thermal efficiency, with 1-1/4" heating connections and a 133 lb dry weight.
De Dietrich
The De Dietrich MCA Pro 90 is a condensing wall-hung boiler rated 55–326 MBH input and 54–306 MBH output at 94.0% CSA thermal efficiency, with 1-1/4" heating connections and a 148 lb dry weight.
The MCA Pro 65 prints 45–222 MBH output and the MCA Pro 90 prints 54–306 MBH output, per the Rv 5.4 submittal.
Yes. Both sizes use 4" single pipe or 100–150 mm concentric venting and the same 3/4" gas and 1-1/4" heating connections.
The 65 at 45 MBH output minimum versus 54 MBH for the 90 — a modest difference that matters mainly in very low-load conditions.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.