20 Most Recent Rinnai Digital Remote Water Heater Control Mcc-45-4us Questions & Answers

I had a similar problem, the water flow control device was bad.
If you disconnect Connector B2 and the unit will start, then that will confirm the problem. Rinnai has a new improved part for replacement.

Rinnai Digital... | Answered on Oct 27, 2017

Try National Energy they are on line they sell spares they may be able to help .

Rinnai Digital... | Answered on Apr 13, 2017

Sounds like there is something loose in the line.Like cut off valve,check valve.

Rinnai Digital... | Answered on Aug 11, 2016

[PDF]Operation / Installation Manual - Rinnai


Rinnai America Corp.temperature (shown on the digital remote control) the gas burner will ... Without the connection of a remote controller(s), the Rinnai Water Heater is preset to.

PDF]Tankless Water Heater Service Manual - Rinnai


Rinnai America Corp.Indicates condensing water heater models. ... Rinnai Water Heater Service Manual. 2 ..... Digital manometer or U tube type manometer with 14 inch water column (W.C.) scale, a hose and two .... will flash on the display of the remote controller.

Rinnai Digital... | Answered on Nov 24, 2015

what i would recommend is to turn power off to unit, turn water off, now open a hot tap inside. Go back to hw unit , turn power back on, now turn HW cold water tap to open. Now you should hear the unit start up.& click continuosly, this is the unit trying to lite. The unit has a flow sensor so as water passes threw it ,that tells unit when to lite. If you hear nothing & no water comming threw you strainer located above cold shut off tap is blocked, unscrew black knob & check. If you have flow & no HW check your gas, usally by losening gas union, there is also filter above this. Also plug another power tool into power point to check you have power

Rinnai Digital... | Answered on May 19, 2014

Probably frozen. Let it thaw out and see if it works. You may want to think about wrapping the pipes with heat tape because of those low tempertures they could break especially if the unit is outside.

Good luck,


Rinnai Digital... | Answered on May 13, 2014

you can get it off the rinnai web site they have a spot on there to get the internet manuel,, but from what you are saying you may need to adjust the thermostat, or the temp, remember even though you will have endless hot water it still takes the smae amount of timed for the hot water to get to your faucet,, not only that make sure your shower heads aren't holding back to much water pressure, if you don't have enough water going thru the unit it will not stay lit, if will come on and go off, judt to dstisfy the unit,, make sure the filter is clear, on the cold side there is a cap screw if you take it off there is a screen in side you just pull it out and clean it and reinstal it,,

Rinnai Digital... | Answered on Nov 27, 2013

What geographic location are you in so I know were to search for the manual please.

Rinnai Digital... | Answered on Jul 27, 2011

Not finding what you are looking for?
Rinnai Digital Remote Water Heater Control Mcc-45-4us Logo

79 questions posted

Ask a Question

Usually answered in minutes!

Top Rinnai Water Heaters Experts


Level 2 Expert

69 Answers

Brad Brown

Level 3 Expert

18403 Answers

Fahr Quad

Level 3 Expert

774 Answers

Are you a Rinnai Water Heater Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

View Most Popular

Rinnai Water Heaters

  • Rinnai Water Heaters

Most Popular Question

am trying increase temperature

  • Water Heaters