Question

where two water heaters are installed in a single house
they must always be installed in the same area
they are typically installed in series
the upstream unit is typically smaller than the downstream unit
the exhaust flues should not be manifolded
parallel systems should have similar pipe lengths to each water heater
question 12
which of the following is not an advantage of combination systems?
there is only one combustion appliance rather than two
it can be a high - efficiency system
we are making use of the domestic hot water in the tank which is kept at the ready anyway
the units can be direct vent so combustion air supply problems are eliminated
these systems are typically oversized for both heating and domestic hot water so there is a lot of capacity

Explanation:

For the first question, in parallel - installed water heaters, having similar pipe lengths helps in balanced water flow and performance. For the second question, being oversized is not an advantage as it can lead to inefficiencies and higher costs.

Answer:

1. parallel systems should have similar pipe lengths to each water heater
2. these systems are typically oversized for both heating and domestic hot water so there is a lot of capacity