Product Overview
The TP-78D is the Mark 17DX-117 ignition control circuit board for Re-Verber-Ray non-flame rod tube heaters operating at 120V, also catalogued under part numbers 2020-70, 2020-93, and 6188148, all identifying the same Detroit Radiant Products Mark 17DX-series direct-sense control board. No third-party equivalent from Honeywell, Cleveland Controls, or Fenwal is documented for this part. The board is the ignition sequencing module housed in the burner control box: it manages the startup and safety sequence for non-flame rod heaters using direct-sense technology, monitoring burner state directly without a remote sensor wand, sequencing gas valve actuation and spark ignition on startup, and locking out on ignition failure or loss of sense signal, which requires a manual reset.
Fits DBS (all BTU), DRV (all BTU), DTH-3 (125 to 150 MBH), DTHS-3 (125 to 150 MBH), and DX with direct sense (all BTU); see the Fitment panel below for the full model list. DX models with remote sense require the TP-351A board instead and are not served by this part. This board is the current direct replacement for the TP-78A (2020-61).
It ships as a single board. The TP-390 wiring adapter required when replacing an older TP-78A (2020-61) is sold separately as a distinct line item.
Re-Verber-Ray's own installation sheet requires that circuit boards be replaced with factory-supplied parts only; do not substitute a generic ignition module. Before replacing this board, shut off the gas supply and disconnect electrical power to the heater. If replacing an older TP-78A (2020-61), install the TP-390 adapter onto the new TP-78D before reconnecting the original wiring harness; adapter orientation is shown in Figure 2 of the installation sheet. This work must be performed by a qualified service person; improper installation, adjustment, service, or maintenance can cause property damage, injury, or death. Verify board selection for your specific model using the Re-Verber-Ray Circuit Board Replacement Installation Sheet (LSH089) before ordering.
Specifications
| Voltage | 120V |
| Heater type | Non Flame Rod Heaters, direct sense ignition only (DX w/remote sense requires TP-351A instead) |
| Compatible series (from install sheet) | DTHS-3 (125-150 MBH), DTH-3 (125-150 MBH), DBS (all inputs), DRV (all inputs), DX w/direct sense (all inputs) |
| Adapter requirement | TP-390 adapter (sold separately) required when replacing old TP-78A (2020-61) circuit board |
| Mounting | Top mounting bolt |
Cross-Reference & Fitment
| Replaces | TP-78A, 2020-61 |
| OEM numbers | 2020-70, 2020-93, Mark 17DX-117, 6188148 |
| Fits | DTHS-3, DTH-3, DBS, DRV, DX |
Documents
- tp-78d-install.pdf (install)
