Defrost Heater Hold Out Relay

[clmanaa]

Installing a Turbo Air walk in freezer ( owner provided the equipment ) and the diagram shows a defrost heater hold out relay "DHR". It shows the hold out relay contacts are wired to the timer term # 3 and to the field supplied heater contactor "DH1". It does not show the hold out relay coil control wiring. And I can not see a need for the hold out relay "DHR". Can anyone explain ? Thanks.

3/01 - I edited / re-phrased the question.

EVAP: ( R404A )
M#: LED168BEM - 4 ECM FANS
S/N: EDNM168249006

15500

[martinw58]

looks like its wired from terminal 3 on timer and terminal 3 on the terminal block that connects to n terminal through high limit stat

[Brian_UK]

On the line from terminal 3 is shown a circle with DH1, that is the defrost heater relay coil.

[clmanaa]

I edited / re-phrased the question.