Charlie Austin prodded Burnley ahead after only 39 seconds but the lead lasted just five minutes before Troy Deeney curled a fine leveller.
Austin took his tally for the season to 28 in the 24th minute, smashing in a penalty after Marco Cassetti tripped Alex Kacaniklic.
But once again Burnley let their lead slip within five minutes, this time when Fernando Forestieri jinked inside Jason Shackell and rifled an angled shot past Lee Grant.
Forestieri thought he has won it for Watford with a 72nd-minute strike from the right-hand corner of the area but instead Vokes made it a happy return to Vicarage Road for Dyche.
Axed by Watford's new owners and replaced by Gianfranco Zola in the summer, Dyche insisted he took no extra satisfaction from the result.
"No, not because it's at this club," he said.
"But I do take great satisfaction in the manner we performed and in the way we got a point after a ding-dong Championship clash.
"I thought the game fluctuated around mistakes to be honest. Charlie is a player with goals in him and I thought he could have had a couple more.
"But I'm not frustrated. Watford are a very good side. They've got every chance."
- Sports & Recreation
- Troy Deeney
- Fernando Forestieri
- Marco Cassetti