Utica Boilers UB90 Series 4 (UB90-50 to UB90-100)

The UB90 Series 4 page describes a 90% AFUE condensing gas boiler in 'a small compact design that's ideal for low-clearance/limited-space applications', with a high-efficiency cast aluminum heat exchanger with low pressure drop, hot surface ignition (HSI) boiler control, a Hydrolevel combination high limit/low water cut-off control with boiler water temperature reset, and a stainless steel premix burner. The page positions the UB90 as a sealed combustion boiler approved for polypropylene venting with an induced draft blower and adjustable exhaust (front, right side or rear), choice of top, side or combination supply/return locations, a low-profile condensate trap, and natural gas or propane options.

As printed in the research headline, the UB90 Series 4 covers UB90-50, UB90-75 and UB90-100 at 90% AFUE with the cast aluminum heat exchanger, HSI and Hydrolevel FuelSmart-style combination control, floor configuration and 50 psi rating; the separate UB90-200 Series II page covers the larger 125-200 MBH sizes on the monoblock heat exchanger and is recorded under its own series. Checked on September 9, 2026, the UB90 Series 4 page's 'Current Documents' tab is populated (UB90 Series 4 IOM Rev. F, parts Rev. G, kit instructions and tech bulletins), so Boilers.ca records productStatus 'current' even though the series is not shown on Utica's condensing category cards.

Like the Q90 twin at Dunkirk, the UB90's Hydrolevel control uses indicator lights rather than discrete fault codes, so no error-code pages are published for the line. The ratings are the US-market figures Utica prints; no Canadian listing was verified on the pages checked, so canadianStatus stays 'unknown'. Gas work belongs with a licensed contractor against the UB90 Series 4 IOM Rev. F (PN 240010135).