Jim's Plumbing


What To Consider When Installing a Rinnai Continuous Flow Hot Water Heater

Rinnai Continuous Flow

We at Jim’s Plumbing have decided to write this short blog of things that a householder should consider before going ahead with installing a Rinnai gas continuous flow hot water system.

It is important that you have a qualified plumber/gas fitter come to your property to make an assessment of what size continuous flow hot water heater you require. Factors we at Jim’s take into consideration include:

  • The number of bathrooms the heater is serving
  • Size of gas pipework that may be required to fuel the Rinnai unit
  • Does the gas meter have enough gas flow?
  • The size of the existing hot and cold pipework
  • Continuous flow heaters are a restricted mains pressure unit

Interest free payment plan options** are available on hot water heater replacements to help ease any financial stress this necessary expense may cause. If your hot water system is leaking, or you have no hot water, we can often have a plumber to you within the hour*.

Number of Bathrooms the Heater is Serving

Rinnai gas heaters come in a variety of sizes which will depend on the size of the unit and how many bathrooms it is providing for. In my experience just looking at the Rinnai catalogue and making a choice of a unit listed as able to feed 2- 3 bathrooms is a mistake without knowing the size of the gas pipework and the flow required.

Size Of Gas Pipework That May Be Required To Fuel The Rinnai Unit

As continuous flow hot water systems require a larger flow of gas than that of a standard storage unit you will need to take into account that depending on the megajoule rating at the meter and the distance the pipework has to travel can often incur more costs than the installation on its own. It is not uncommon for a new gas supply needing to be run from your gas meter to the new hot water position so that sufficient gas can be used to run the unit. Many customers elect to go ahead with the extra expense and pipe alterations just to have the convenience of a Rinnai continuous flow so that they are never running out of hot water which a storage unit has a tendency to do when the demand is high.

Does The Gas Meter Have Enough Gas Flow

Your Jim’s Plumbing Rinnai specialist will check your gas meter and check the megajoule rating that it is able to produce. This is very important as in areas where the gas pressures are low continuous flow units cannot be used as there is insufficient gas flow to operate these at the manufacturer’s specified settings. Some customers can approach their gas authority who may be able to, in areas where there is low gas flow, put a larger gas meter in which will produce larger gas supply and reducing the size of pipework required to be run to the position of the new unit. We sometimes have had to run 50mm copper (which is expensive) in jobs where the customer has not increased the gas meter or gas pressure is too low.

The Size Of The Existing Hot And Cold Pipework

A plumber will need to check the size of the existing cold supply to the hot water unit and also the hot outlet pipework sizing as customers can be disappointed that their unit may only supply one fixture at a given time. You can put a larger 26 Rinnai which in their catalogue says feeds more than 1 bathroom, but if there is only 15mm water pipework there is not enough flow to do so. This is something we always advise customers to take into account with any continuous flow hot water units.

Continuous Flow Heaters Are A Restricted Mains Pressure Unit

Customers need to be aware that any instantaneous or continuous flow units normally will not produce the same hot water pressure than that of a storage mains pressure type they may have had previously.

Rinnai Installed

Once a Rinnai hot water system has been installed it is essential that you ask your plumber/gas fitter to check the water in the shower as many older shower roses are too restrictive in delivering hot water and the unit will detect it as a fault thus not producing hot water or intermittent hot water. Sometimes the shower rose to need to be replaced to alleviate this problem.

When changing to a Rinnai instantaneous hot water unit the purchase price of the unit may be only a percentage of the true cost of when it is installed. The below extra costs include:

  • Upgrading of the gas pipework as this is often required.
  • Altering the hot and cold pipework to now suit a cont flow unit.
  • Electrical costs for an electrician as a powerpoint is required to run the ignition system.
  • Labour and materials.

Choosing the correct hot water system can be difficult, as there are so many options to choose from.

Simply book a plumber online now, or phone 1300 133 509 to book now.

Please be advised that we have additional hot water system brands & models available.

15 Years of Service
15 Years of Service