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    A Singular Solution From Bosch

    June 15, 2021
    Bosch’s Singular combi boiler provides efficient and reliable heat and hot water in one cost-effective, wall-mounted product.

    The townhouse near the college. The ranch with a radiant floor out in the suburbs. The duplex uptown. The loft downtown. The weekend cabin at the lake. They all want to upgrade, and they all need both domestic hot water and hydronic heat. I’m thinking my quotes would be more competitive if there was one appliance from one source that can handle both. Why install a water heater and a boiler when one can do both?

    Right now, I get my instantaneous water heaters from a couple of wholesalers and my boilers from different wholesalers. My install crew is complaining about the confusion of different manufacturers’ requirements because they like to know what comes with the unit and what doesn’t. My service crew wants training from a single brand source, to learn the tricks of the controls and setups. My bookkeeper wants fewer vendors so there are fewer checks to cut. Life is not easy with so many complaints.

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    How about that idea of one source? The sales guys for a few of the boiler brands I currently buy have been sending me info on their offerings, but I really want to get to a single source from a brand I trust and my prospects recognize. Would that raise the morale of the company, make the jobs go more smoothly, and also reduce those annoyingly expensive call backs?

    It wasn’t hard to find out that there is one appliance that does both domestic water and space heating, by Bosch, a brand with a great reputation for quality, backup and consumer brand awareness. The product is the Singular, and it’s Bosch’s newest model which has an AFUE rating of 95%, and features an eco-friendly low NOx metal fiber burner.

    Everything, including the boiler pump, is installed and wired in a compact size (18.11” W x 31.87” H) cabinet that mounts on the wall and saves space, which homeowners like. The low water cutoff is also already installed and wired. There’s no more adapting the piping for the installation of the LWCO, which eliminates another potential place for a water leak; and, no more hunting around for a wiring diagram, which saves time and reduces frustration.

    It only weighs 80 pounds and is easier to maneuver and take down steps.

    Because the Singular model comes in two sizes, I can tailor the size to the job. The domestic hot water output of the 4000 model can handle up to two showers running continuously, while the 5200 model handles three showers. The sizing for domestic is like what I’m familiar with already.

    The Singular 4000’s heat capacity for space heating is 19,900 to 80,000 BTU/H.

    For the Singular 5200, heat capacity for space heating goes from 19,900 to 140,000 BTU/H.

    The Singular 4000’s heat capacity for domestic hot water is 19,900 to 155,000 BTU/H.

    The Singular 5200 has a domestic hot water capacity of 19,900 to 199,000 BTU/H.

    Temperature range for space heating in both models is 82 degrees F to 180 degrees F. For direct hot water, the temperature range for both models is 86 degrees F to 140 degrees F.

    What I really like about using the Singular for domestic hot water is how little the heat exchanger will have to be cleaned, since it is completely different from a regular instantaneous water heater. There are two stainless steel heat exchangers involved in the Singular. The gas burner heats water in the boiler heat exchanger, and that hot water is pumped through one side of a separate brazed plate heat exchanger to heat the incoming cold water flowing through the other side.

    That’s important because a regular instantaneous uses the 400-degree flame to heat the incoming cold water, while the Singular uses 180-degree water to heat the incoming water. I know that higher heat causes faster fouling, so using half the temperature will significantly reduce fouling, which increases the time between cleanings. My customers will appreciate the savings and my crews can be out doing more profitable jobs.

    This combi is perfect for fuel oil to gas conversions. If we’re hooking it up to natural gas, it’s ready to go. If we’re hooking it up to propane, we can just install the provided conversion kit before hanging it on the wall.

    Installing a new flue is required when using a high efficiency gas appliance, and Bosch gives me the flexibility to use a variety of flue materials. I can still use PVC where I’m allowed—my crews are familiar with it and availability is good. I can use CPVC, but polypropylene, which is also approved, is less expensive and becoming more available every day. The vent pipe lengths are generous, 2” pipe can go up to 60 feet, while 3” pipe can go as far as 150 feet. An exhaust gas temperature sensor ensures safe operation.

    My install manager loves the convenience of the space heating connections since the boiler pump is already installed—that’s one side of a primary secondary connection that’s already done. If the space heating application is a single zone with minimal pressure drop (like a cast iron radiator job with one t-stat and huge pipes) he can just pipe it as full flow, using the already installed pump. I like it when he likes something.

    The cabinet is small, but packs in a lot of domestic hot water capacity and space heating features. The convenience of both domestic hot water and space heating from one source simplifies installation, service and billing, which frees me up to concentrate on figuring out how to grow my business. I’ll be quoting this on those projects I mentioned at the beginning: the townhouse, the ranch, the duplex, the loft and the cabin.

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