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Seattle Townhouse Heating & Hot Water Systems

Townhouse Combination Heating & Domestic Hot Water Systems

as typically installed in Seattle Washington

In the Seattle PI, we were ranked as among the very Best plumbing companies in Seattle

Call us at (206) 281-8855 if you need assistance with this type of equipment or Contact us via email

In our experience servicing this type of system, we have formed the following professional opinions about them:

The water heater should be changed to a hot water boileror water heater that is designed for continuous duty and rated for the maximum heat load.

The domestic water should be isolated from the space heating portion of the system to prevent high bacteria counts from contaminating the potable water supply.

Townhouses built in the City of Seattle in the last decade typically use a combination hot water system that many homeowners find difficult to live with.

The systems we see usually have these characteristics:

  1. The space heating water is shared with the domestic hot water supply increasing bacteria contamination risks.

  2. The system was installed by unskilled workers

  3. The system was not intelligently designed

  4. The water heater is undersized for the heat load making it difficult to heat the house in the winter and making cool showers.

  5. There are limitations in replacing with more suitable equipment - both structurally and economically.

  6. This type of system was typically installed by speculation builders with the cost of the system being the sole consideration - not suitability, longevity, safety or reliability. They went cheap upfront but the cost to run them and service them is high.

These water heaters were never designed to heat houses.

They are light-duty intermittant-use domestic water heaters. They were engineered to heat water for the shower, sink and laundry. They are built to heat water for up to an hour and then turn off until the next use. When used to heat the house they can run 24 hours a day continuously. The machine gets overstressed. We have seen metal fatique, burner distruction, flue baffles crumbled onto the burners, pilot wiring fried, inducer motor housing melted, flue pipes cooked until they crack. Needless to say, as service mechanics we do not think that these machines are reliable or predictably safe to operate when used as combination heating/domestic water makers.

This one is put together a little better than some but it is still underpowered and it needs a heat exchanger to separate the radiant water from the domestic water.

Bacteria Risks: When there is no need to heat the radiators, the circulation pump turns off, leaving water in the radiant piping and radiators to sit and become stagnant, sometimes for months. When the heating season starts, all that stagnant water gets pumped into the domestic tank, contaminating your shower, lavatory and kitchen faucet water with high levels of bacteria.

This picture shows a couple of zone valves which shows some attempt at real temperature control of the radiant loops, which most lack.

Many of these installations position the equipment in an inside utility space (not on an outside wall) so there are serious restrictions with retrofitting a larger or different type of heater and/or flue pipe or increasing the size of the gas pipe. Installing a tankless water heater as a replacement requires a bigger gas line and a different size or type of flue pipe.

Give us a call if you need a consultation of your options for repairing, retrofitting or replacing this type of heating system.

Call Evan at (206) 281-8855